Kalshi's taker fee is 0.07 × contracts × price × (1 − price), times the series multiplier (1 by default) and rounded up to the next cent, so it peaks at 1.75¢ per contract at a 50¢ price. Resting (maker) orders are free on standard series and pay a fee only on the series Kalshi lists with maker fees.
Country-by-country rules, regulator actions and sources for Polymarket and Kalshi.
This is not legal advice, and we don't say whether trading is legal for you in Japan. We report what each platform's published rules say about Japan and the public regulator, court and police actions we could source, each with a date. Those rules change fast, so check the platform's current terms and the law in Japan before doing anything. ‘Not listed’ only means a platform's own list doesn't name Japan; it doesn't mean trading there is permitted.
Status under each platform's own published rules, and the most recent public action we could source, as of 2026-09-24.
No public action found as of 2026-09-24
Dated public actions on record: 0
This page keeps two things apart for Japan: what each platform's own published rules say, and what regulators, courts and police in Japan have publicly done. A platform's list is its own policy and a government order is the government's, so a country can be on one and not the other.
The status labels are the same as in the main table. Restricted means the platform's own list blocks trading from Japan. Close-only means existing users there can close positions but can't open new ones. Some regions means only named regions are restricted. Separate product means residents use a different, separately regulated product, as US residents do with the Polymarket US app. Not listed means the platform's published list doesn't name Japan; that is not the same as permitted, and a regulator may still block the site.
Polymarket publishes two official lists that don't fully match: its Help Center page (updated August 14, 2026) and its developer docs (undated). We follow the dated Help Center list and say where the developer docs differ. Kalshi statuses follow its Member Agreement as fetched on September 24, 2026; the agreement itself is undated.
Each action shows the authority as it names itself, what it did, the platform it concerns and the date: the date of the action where it was published, otherwise the date it was first reported. Every entry is marked Official, Platform document or Secondary report. Where only secondary reporting exists, we say ‘reported by’ and name the outlet; where official sources conflict, we report both.
‘No public action found’ means our searches found none, not that none exists. Nothing on this page says whether trading is legal for you: for that, check the platforms' current terms and the law in Japan.
Polymarket's two official lists disagree about Japan. Its Help Center page on geographic restrictions, updated August 14, 2026, puts Japan among the 39 countries it calls blocked. Its undated developer geoblock documentation puts Japan in the tier ‘close-only on frontend only (API not restricted)’, alongside Ireland, Malta (sports only), the Netherlands and South Korea. We follow the dated Help Center list, so Japan is Restricted for Polymarket under this site's labels, with a note that the developer docs describe a narrower, close-only restriction.
CoinPost reported on April 27, 2026 that Polymarket had added Japan to its own restricted list that month (33 countries at the time), gating the trading interface for Japanese IP addresses but not the API, and described the change as regulatory compliance rather than a sanctions block. Polymarket has published no changelog, so the exact date of the change is unknown. The site itself still loads from Japan: Polymarket serves a Japanese-language interface and a Japan topic page, which is why search results can show it as ‘available’ while trading is restricted. We found no Japanese ISP or DNS block, no app-store removal order and no court order; the only restriction we found is Polymarket's own.
Kalshi's Member Agreement (Section VI, ‘Restricted Jurisdictions’, undated; fetched September 24, 2026) doesn't name Japan, and Japan wasn't on the Exchange Notices of October 23, 2025 or November 4, 2025 either. Under this site's labels Japan is Not listed for Kalshi. Kalshi's help center (updated March 20, 2026) says trading from outside the United States is subject to the Member Agreement. We found no Kalshi blog post or notice naming Japan. ‘Not listed’ describes Kalshi's contract only: the FSA's and the police's statements below don't distinguish between platforms, and Kalshi's absence from the list says nothing about Japanese law.
Japan has no regulator dedicated to prediction markets. The Financial Services Agency (FSA, 金融庁) supervises securities and derivatives under the Financial Instruments and Exchange Act and crypto-asset exchanges under the Payment Services Act. At the House of Councillors Committee on Financial Affairs on April 21, 2026, answering a question from Shuichi Harada (Democratic Party for the People), Toshitaka Inoue, Director-General of the FSA's Planning and Markets Bureau, said there is currently no law or department that directly regulates prediction markets, that they raise gambling-offence and insider-trading concerns, and that the agency ‘must respond extremely cautiously’ (極めて慎重に対応する必要がある). The exchange was reported by JinaCoin on April 22, 2026 and CoinPost on April 27, 2026 (secondary; we did not fetch the Diet minutes).
The gambling offences are enforced by the National Police Agency and prefectural police under the Penal Code: Article 185 (simple gambling, punishable by a fine of up to ¥500,000 or a petty fine), Article 186(1) (habitual gambling, up to 3 years' custody) and Article 186(2) (running a gambling place for profit). The Osaka Prefectural Police page on online casinos states that betting from inside Japan on an online site is a gambling offence ‘even if the site is legally operated abroad’ (undated; it notes the June 1, 2025 change of the custodial term's wording to 拘禁刑). Those police pages are about online casinos and don't name Polymarket or Kalshi. The exceptions to the gambling ban are statutory: public racing, the lottery, sports toto and the integrated-resort framework, as NADA NEWS summarised on May 25, 2026.
Public actions naming Polymarket or Kalshi: none by a government body. Our searches in Japanese and English through September 26, 2026 found no FSA, National Police Agency, Consumer Affairs Agency or court action naming either platform, no ISP block, no app-store order and no court challenge, which is why the timeline below is empty. That means we found none, not that none exists. The one dated restriction is private: on June 15, 2026, an FSA-registered Japanese crypto-asset exchange published a notice (‘【重要】予測市場サービスの利用に関する注意喚起’) that names Polymarket, says that using such services from Japan for money ‘may constitute gambling or similar prohibited conduct’ (賭博行為等に該当する可能性), and states that accounts with deposits or withdrawals linked to prediction-market services will be suspended, with login, crypto-asset deposits and withdrawals, yen withdrawals and trading all disabled and a contact route for mistaken suspensions (the exchange's own notice, primary; also reported by CoinPost on June 15, 2026). We found no similar notice from any other Japanese exchange or from the industry self-regulatory body.
The entries below are rendered from the same dated data as the main country table, newest first. Each row shows the date, the authority as it names itself, the type of action, the platform it concerns and the source with its type.
No public action found. As of 2026-09-24, our searches found no regulator, court or police action naming Polymarket or Kalshi in Japan. That means we found none, not that none exists.
This section reports what the law and the authorities in Japan have said about people who take part in these markets, and any enforcement against users that has been made public. It describes; it doesn't advise.
We found no statement by a Japanese authority about penalties for Polymarket or Kalshi users specifically. The only official user-facing position is the general one above: the police say that betting from inside Japan on an online site is an offence under Articles 185 and 186 of the Penal Code even when the site is lawfully run abroad, and that position was published about online casinos. We found no prosecution or arrest linked to prediction markets, no National Tax Agency statement on prediction-market winnings, and no bank or payment restriction other than the account-suspension policy that an FSA-registered crypto-asset exchange announced on June 15, 2026.
Law-firm commentary, which is not official guidance, treats crypto-based prediction markets as likely gambling for both operator and participant: So & Sato's analysis of June 15, 2026 discusses Articles 185 and 186(2), the Financial Instruments and Exchange Act and the Unfair Competition Prevention Act, and Parks Law Office's note of August 15, 2026, citing the Supreme Court's 1948 and Tokyo District Court's 2015 definitions of chance, says that as of August 2026 no Japanese court ruling or official guidance addresses a Polymarket-type structure. A Dai-ichi Life Research Institute report of June 11, 2026 likewise warns that trading for money on prediction markets from Japan ‘may fall foul of the gambling offence’.
Polymarket is seeking a licensed route into Japan. CoinDesk reported on May 22, 2026 that Polymarket had appointed Mike Eidlin to run its Japan efforts, with a target of regulatory approval by 2030 and coordination with lawyers, industry bodies and regulators; NADA NEWS carried the same report via Yahoo Finance Japan on May 25, 2026 (secondary).
On September 15, 2026, NADA NEWS reported, as a single-outlet exclusive, that the Liberal Democratic Party's lawmakers' league on digital advanced finance (デジタル先端金融議員連盟) had taken up prediction markets as a study theme, focusing on how to reconcile them with the gambling offence and the Financial Instruments and Exchange Act, and that Polymarket and Kalshi executives were planning visits to Japan. We found no bill or policy that followed as of September 26, 2026.
In the same Diet answer of April 21, 2026, the FSA official pointed to a suspicious sell order of roughly ¥150 billion in crude-oil futures placed before the ceasefire announcement of April 7, 2026 as an example of the insider-trading risk on decentralised venues, as reported by JinaCoin on April 22, 2026.
PolyKal is a read-only research site, and it does not restrict access by country, including from Japan. Its public pages, including prices on both platforms, order-book depth, after-fee cost comparisons, the fee calculator, and large-trade and whale data, need no account. You don't need a VPN to use them.
Viewing public market data is not trading. PolyKal doesn't place orders, hold funds or give access to trading on either platform, and a restriction on Polymarket or Kalshi in Japan still applies to trading there. Polymarket's help center says that using a VPN to get around its restrictions violates its Terms of Use, and Kalshi's Member Agreement excludes people in its restricted jurisdictions; getting around a block can also break local law. PolyKal doesn't help anyone get around them.
Start with the compare page, the fee calculator or large trades, or read how Polymarket works and how Kalshi works.
Japan is one of 27 countries, plus the United States, that PolyKal tracks. The full availability table shows every country's status under each platform's rules and its regulator actions side by side, with the same dates and sources as this page, and its change log lists every edit we make.
Every entry is re-checked at least once a quarter, and sooner when a platform or regulator announces a change. The next scheduled full re-check is shown in the sidebar.
We found no Japanese court ruling or regulator decision on it, and we don't decide it for you. What the record shows: the FSA told the House of Councillors on April 21, 2026 that no law or department directly regulates prediction markets and that it must act ‘extremely cautiously’; the police's general position is that betting from Japan on an online site is a gambling offence under Penal Code Articles 185 and 186 even if the site is lawfully run abroad; and Polymarket's own Help Center lists Japan as blocked. Check the current law and the platform's current terms before doing anything.
Not by the government: we found no Japanese order, court ruling or police action naming Polymarket as of September 26, 2026. The restriction is Polymarket's own. Its Help Center (updated August 14, 2026) lists Japan as blocked, and its developer docs describe a close-only restriction on the website only; CoinPost reported the change in April 2026. The site still loads from Japan, but trading from a Japanese IP address is gated by the platform.
Kalshi's Member Agreement (fetched September 24, 2026) doesn't list Japan as a restricted jurisdiction, and its help center says international trading is subject to that agreement. That is Kalshi's contract, not a statement about Japanese law: the FSA's and the police's positions described on this page apply regardless of platform, and we found no Japanese authority that has addressed Kalshi by name.
We found no court decision on that. The FSA said on April 21, 2026 that prediction markets raise gambling-offence and insider-trading concerns and that no law directly regulates them. Law firms So & Sato (June 15, 2026) and Parks Law Office (August 15, 2026) consider crypto prediction markets likely to fall under Penal Code Articles 185 and 186, while noting that no Japanese ruling or official guidance addresses a Polymarket-type structure; an FSA-registered crypto-asset exchange's notice of June 15, 2026 says such use ‘may constitute gambling or similar prohibited conduct’. Those are opinions and a private company's policy, not a ruling.
Yes, on PolyKal. Its pages load from Japan without an account and show prices, order-book depth and after-fee comparisons for both platforms. Viewing data is not trading: PolyKal doesn't place orders or hold funds, and Polymarket's restriction on Japan, and the legal positions described on this page, still apply to trading.
No. Polymarket's help center says that using a VPN to get around its restrictions violates its Terms of Use, and Kalshi's Member Agreement excludes people in its restricted jurisdictions. Getting around a block can also break local law. You don't need a VPN to research these markets: PolyKal's prices, order books and fee calculator don't require one.
We re-check every country page at least once a quarter, and sooner when a platform or regulator announces a change; each rule and action on the page shows its own date and source. If you spot something out of date for Japan, email [email protected] with a link to the new rule or order.
Every statement on this page rests on the sources below. Platform rules were checked against Polymarket's and Kalshi's own pages on September 24, 2026; regulator, court and police actions were checked against the sources listed on September 24–26, 2026. Each source is marked as official, a platform document or a secondary report. Where only secondary reporting was available, we cite it and say so; where official sources conflict, we report both. We re-verify this page quarterly.
JinaCoin: FSA answer on prediction markets at the House of Councillors Committee on Financial Affairs, April 22, 2026 (session of April 21, 2026). Secondary; Diet minutes not fetched. CoinPost: FSA answer and Polymarket's addition of Japan to its restricted list, April 27, 2026. Secondary.
Osaka Prefectural Police: online casinos and the gambling offences (Penal Code Articles 185 and 186), undated. Official; concerns online casinos and names no platform.
Notice by an FSA-registered crypto-asset exchange on the use of prediction-market services (【重要】予測市場サービスの利用に関する注意喚起), June 15, 2026. Primary notice of a private company; neither an official nor a platform document. CoinPost on that exchange's notice, June 15, 2026. Secondary.
So & Sato: Is Polymarket gambling or prediction infrastructure?, June 15, 2026. Secondary (law-firm commentary). Parks Law Office: prediction markets and the gambling offence, August 15, 2026. Secondary (law-firm commentary). Dai-ichi Life Research Institute report on prediction markets, June 11, 2026. Secondary.
CoinDesk: Polymarket aims for prediction-market approval in Japan by 2030, May 22, 2026. Secondary. NADA NEWS via Yahoo Finance Japan on the same appointment and the statutory gambling exceptions, May 25, 2026. Secondary. NADA NEWS: LDP lawmakers' league takes up prediction markets, September 15, 2026. Secondary; single-outlet exclusive.
Platform documents (all countries): Polymarket Help Center: Geographic restrictions (updated August 14, 2026), Polymarket developer docs: Geoblock (undated), Kalshi Member Agreement (undated; fetched September 24, 2026) and Kalshi Help Center: trading from outside the US (updated March 20, 2026).
PolyKal is an independent research tool. We are not affiliated with, endorsed by, or operated by Polymarket or Kalshi. We report each platform's published rules and public regulator, court and police actions in Japan; we don't say whether trading is legal for you, and we don't help anyone get around a platform's restrictions. Last reviewed September 26, 2026. Not legal or financial advice.
Know of a newer rule, order or court decision for Japan? Email [email protected] with a link to it.
Kalshi's taker fee is 0.07 × contracts × price × (1 − price), times the series multiplier (1 by default) and rounded up to the next cent, so it peaks at 1.75¢ per contract at a 50¢ price. Resting (maker) orders are free on standard series and pay a fee only on the series Kalshi lists with maker fees.
Country-by-country rules, regulator actions and sources for Polymarket and Kalshi.
This is not legal advice, and we don't say whether trading is legal for you in Japan. We report what each platform's published rules say about Japan and the public regulator, court and police actions we could source, each with a date. Those rules change fast, so check the platform's current terms and the law in Japan before doing anything. ‘Not listed’ only means a platform's own list doesn't name Japan; it doesn't mean trading there is permitted.
Status under each platform's own published rules, and the most recent public action we could source, as of 2026-09-24.
No public action found as of 2026-09-24
Dated public actions on record: 0
This page keeps two things apart for Japan: what each platform's own published rules say, and what regulators, courts and police in Japan have publicly done. A platform's list is its own policy and a government order is the government's, so a country can be on one and not the other.
The status labels are the same as in the main table. Restricted means the platform's own list blocks trading from Japan. Close-only means existing users there can close positions but can't open new ones. Some regions means only named regions are restricted. Separate product means residents use a different, separately regulated product, as US residents do with the Polymarket US app. Not listed means the platform's published list doesn't name Japan; that is not the same as permitted, and a regulator may still block the site.
Polymarket publishes two official lists that don't fully match: its Help Center page (updated August 14, 2026) and its developer docs (undated). We follow the dated Help Center list and say where the developer docs differ. Kalshi statuses follow its Member Agreement as fetched on September 24, 2026; the agreement itself is undated.
Each action shows the authority as it names itself, what it did, the platform it concerns and the date: the date of the action where it was published, otherwise the date it was first reported. Every entry is marked Official, Platform document or Secondary report. Where only secondary reporting exists, we say ‘reported by’ and name the outlet; where official sources conflict, we report both.
‘No public action found’ means our searches found none, not that none exists. Nothing on this page says whether trading is legal for you: for that, check the platforms' current terms and the law in Japan.
Polymarket's two official lists disagree about Japan. Its Help Center page on geographic restrictions, updated August 14, 2026, puts Japan among the 39 countries it calls blocked. Its undated developer geoblock documentation puts Japan in the tier ‘close-only on frontend only (API not restricted)’, alongside Ireland, Malta (sports only), the Netherlands and South Korea. We follow the dated Help Center list, so Japan is Restricted for Polymarket under this site's labels, with a note that the developer docs describe a narrower, close-only restriction.
CoinPost reported on April 27, 2026 that Polymarket had added Japan to its own restricted list that month (33 countries at the time), gating the trading interface for Japanese IP addresses but not the API, and described the change as regulatory compliance rather than a sanctions block. Polymarket has published no changelog, so the exact date of the change is unknown. The site itself still loads from Japan: Polymarket serves a Japanese-language interface and a Japan topic page, which is why search results can show it as ‘available’ while trading is restricted. We found no Japanese ISP or DNS block, no app-store removal order and no court order; the only restriction we found is Polymarket's own.
Kalshi's Member Agreement (Section VI, ‘Restricted Jurisdictions’, undated; fetched September 24, 2026) doesn't name Japan, and Japan wasn't on the Exchange Notices of October 23, 2025 or November 4, 2025 either. Under this site's labels Japan is Not listed for Kalshi. Kalshi's help center (updated March 20, 2026) says trading from outside the United States is subject to the Member Agreement. We found no Kalshi blog post or notice naming Japan. ‘Not listed’ describes Kalshi's contract only: the FSA's and the police's statements below don't distinguish between platforms, and Kalshi's absence from the list says nothing about Japanese law.
Japan has no regulator dedicated to prediction markets. The Financial Services Agency (FSA, 金融庁) supervises securities and derivatives under the Financial Instruments and Exchange Act and crypto-asset exchanges under the Payment Services Act. At the House of Councillors Committee on Financial Affairs on April 21, 2026, answering a question from Shuichi Harada (Democratic Party for the People), Toshitaka Inoue, Director-General of the FSA's Planning and Markets Bureau, said there is currently no law or department that directly regulates prediction markets, that they raise gambling-offence and insider-trading concerns, and that the agency ‘must respond extremely cautiously’ (極めて慎重に対応する必要がある). The exchange was reported by JinaCoin on April 22, 2026 and CoinPost on April 27, 2026 (secondary; we did not fetch the Diet minutes).
The gambling offences are enforced by the National Police Agency and prefectural police under the Penal Code: Article 185 (simple gambling, punishable by a fine of up to ¥500,000 or a petty fine), Article 186(1) (habitual gambling, up to 3 years' custody) and Article 186(2) (running a gambling place for profit). The Osaka Prefectural Police page on online casinos states that betting from inside Japan on an online site is a gambling offence ‘even if the site is legally operated abroad’ (undated; it notes the June 1, 2025 change of the custodial term's wording to 拘禁刑). Those police pages are about online casinos and don't name Polymarket or Kalshi. The exceptions to the gambling ban are statutory: public racing, the lottery, sports toto and the integrated-resort framework, as NADA NEWS summarised on May 25, 2026.
Public actions naming Polymarket or Kalshi: none by a government body. Our searches in Japanese and English through September 26, 2026 found no FSA, National Police Agency, Consumer Affairs Agency or court action naming either platform, no ISP block, no app-store order and no court challenge, which is why the timeline below is empty. That means we found none, not that none exists. The one dated restriction is private: on June 15, 2026, an FSA-registered Japanese crypto-asset exchange published a notice (‘【重要】予測市場サービスの利用に関する注意喚起’) that names Polymarket, says that using such services from Japan for money ‘may constitute gambling or similar prohibited conduct’ (賭博行為等に該当する可能性), and states that accounts with deposits or withdrawals linked to prediction-market services will be suspended, with login, crypto-asset deposits and withdrawals, yen withdrawals and trading all disabled and a contact route for mistaken suspensions (the exchange's own notice, primary; also reported by CoinPost on June 15, 2026). We found no similar notice from any other Japanese exchange or from the industry self-regulatory body.
The entries below are rendered from the same dated data as the main country table, newest first. Each row shows the date, the authority as it names itself, the type of action, the platform it concerns and the source with its type.
No public action found. As of 2026-09-24, our searches found no regulator, court or police action naming Polymarket or Kalshi in Japan. That means we found none, not that none exists.
This section reports what the law and the authorities in Japan have said about people who take part in these markets, and any enforcement against users that has been made public. It describes; it doesn't advise.
We found no statement by a Japanese authority about penalties for Polymarket or Kalshi users specifically. The only official user-facing position is the general one above: the police say that betting from inside Japan on an online site is an offence under Articles 185 and 186 of the Penal Code even when the site is lawfully run abroad, and that position was published about online casinos. We found no prosecution or arrest linked to prediction markets, no National Tax Agency statement on prediction-market winnings, and no bank or payment restriction other than the account-suspension policy that an FSA-registered crypto-asset exchange announced on June 15, 2026.
Law-firm commentary, which is not official guidance, treats crypto-based prediction markets as likely gambling for both operator and participant: So & Sato's analysis of June 15, 2026 discusses Articles 185 and 186(2), the Financial Instruments and Exchange Act and the Unfair Competition Prevention Act, and Parks Law Office's note of August 15, 2026, citing the Supreme Court's 1948 and Tokyo District Court's 2015 definitions of chance, says that as of August 2026 no Japanese court ruling or official guidance addresses a Polymarket-type structure. A Dai-ichi Life Research Institute report of June 11, 2026 likewise warns that trading for money on prediction markets from Japan ‘may fall foul of the gambling offence’.
Polymarket is seeking a licensed route into Japan. CoinDesk reported on May 22, 2026 that Polymarket had appointed Mike Eidlin to run its Japan efforts, with a target of regulatory approval by 2030 and coordination with lawyers, industry bodies and regulators; NADA NEWS carried the same report via Yahoo Finance Japan on May 25, 2026 (secondary).
On September 15, 2026, NADA NEWS reported, as a single-outlet exclusive, that the Liberal Democratic Party's lawmakers' league on digital advanced finance (デジタル先端金融議員連盟) had taken up prediction markets as a study theme, focusing on how to reconcile them with the gambling offence and the Financial Instruments and Exchange Act, and that Polymarket and Kalshi executives were planning visits to Japan. We found no bill or policy that followed as of September 26, 2026.
In the same Diet answer of April 21, 2026, the FSA official pointed to a suspicious sell order of roughly ¥150 billion in crude-oil futures placed before the ceasefire announcement of April 7, 2026 as an example of the insider-trading risk on decentralised venues, as reported by JinaCoin on April 22, 2026.
PolyKal is a read-only research site, and it does not restrict access by country, including from Japan. Its public pages, including prices on both platforms, order-book depth, after-fee cost comparisons, the fee calculator, and large-trade and whale data, need no account. You don't need a VPN to use them.
Viewing public market data is not trading. PolyKal doesn't place orders, hold funds or give access to trading on either platform, and a restriction on Polymarket or Kalshi in Japan still applies to trading there. Polymarket's help center says that using a VPN to get around its restrictions violates its Terms of Use, and Kalshi's Member Agreement excludes people in its restricted jurisdictions; getting around a block can also break local law. PolyKal doesn't help anyone get around them.
Start with the compare page, the fee calculator or large trades, or read how Polymarket works and how Kalshi works.
Japan is one of 27 countries, plus the United States, that PolyKal tracks. The full availability table shows every country's status under each platform's rules and its regulator actions side by side, with the same dates and sources as this page, and its change log lists every edit we make.
Every entry is re-checked at least once a quarter, and sooner when a platform or regulator announces a change. The next scheduled full re-check is shown in the sidebar.
We found no Japanese court ruling or regulator decision on it, and we don't decide it for you. What the record shows: the FSA told the House of Councillors on April 21, 2026 that no law or department directly regulates prediction markets and that it must act ‘extremely cautiously’; the police's general position is that betting from Japan on an online site is a gambling offence under Penal Code Articles 185 and 186 even if the site is lawfully run abroad; and Polymarket's own Help Center lists Japan as blocked. Check the current law and the platform's current terms before doing anything.
Not by the government: we found no Japanese order, court ruling or police action naming Polymarket as of September 26, 2026. The restriction is Polymarket's own. Its Help Center (updated August 14, 2026) lists Japan as blocked, and its developer docs describe a close-only restriction on the website only; CoinPost reported the change in April 2026. The site still loads from Japan, but trading from a Japanese IP address is gated by the platform.
Kalshi's Member Agreement (fetched September 24, 2026) doesn't list Japan as a restricted jurisdiction, and its help center says international trading is subject to that agreement. That is Kalshi's contract, not a statement about Japanese law: the FSA's and the police's positions described on this page apply regardless of platform, and we found no Japanese authority that has addressed Kalshi by name.
We found no court decision on that. The FSA said on April 21, 2026 that prediction markets raise gambling-offence and insider-trading concerns and that no law directly regulates them. Law firms So & Sato (June 15, 2026) and Parks Law Office (August 15, 2026) consider crypto prediction markets likely to fall under Penal Code Articles 185 and 186, while noting that no Japanese ruling or official guidance addresses a Polymarket-type structure; an FSA-registered crypto-asset exchange's notice of June 15, 2026 says such use ‘may constitute gambling or similar prohibited conduct’. Those are opinions and a private company's policy, not a ruling.
Yes, on PolyKal. Its pages load from Japan without an account and show prices, order-book depth and after-fee comparisons for both platforms. Viewing data is not trading: PolyKal doesn't place orders or hold funds, and Polymarket's restriction on Japan, and the legal positions described on this page, still apply to trading.
No. Polymarket's help center says that using a VPN to get around its restrictions violates its Terms of Use, and Kalshi's Member Agreement excludes people in its restricted jurisdictions. Getting around a block can also break local law. You don't need a VPN to research these markets: PolyKal's prices, order books and fee calculator don't require one.
We re-check every country page at least once a quarter, and sooner when a platform or regulator announces a change; each rule and action on the page shows its own date and source. If you spot something out of date for Japan, email [email protected] with a link to the new rule or order.
Every statement on this page rests on the sources below. Platform rules were checked against Polymarket's and Kalshi's own pages on September 24, 2026; regulator, court and police actions were checked against the sources listed on September 24–26, 2026. Each source is marked as official, a platform document or a secondary report. Where only secondary reporting was available, we cite it and say so; where official sources conflict, we report both. We re-verify this page quarterly.
JinaCoin: FSA answer on prediction markets at the House of Councillors Committee on Financial Affairs, April 22, 2026 (session of April 21, 2026). Secondary; Diet minutes not fetched. CoinPost: FSA answer and Polymarket's addition of Japan to its restricted list, April 27, 2026. Secondary.
Osaka Prefectural Police: online casinos and the gambling offences (Penal Code Articles 185 and 186), undated. Official; concerns online casinos and names no platform.
Notice by an FSA-registered crypto-asset exchange on the use of prediction-market services (【重要】予測市場サービスの利用に関する注意喚起), June 15, 2026. Primary notice of a private company; neither an official nor a platform document. CoinPost on that exchange's notice, June 15, 2026. Secondary.
So & Sato: Is Polymarket gambling or prediction infrastructure?, June 15, 2026. Secondary (law-firm commentary). Parks Law Office: prediction markets and the gambling offence, August 15, 2026. Secondary (law-firm commentary). Dai-ichi Life Research Institute report on prediction markets, June 11, 2026. Secondary.
CoinDesk: Polymarket aims for prediction-market approval in Japan by 2030, May 22, 2026. Secondary. NADA NEWS via Yahoo Finance Japan on the same appointment and the statutory gambling exceptions, May 25, 2026. Secondary. NADA NEWS: LDP lawmakers' league takes up prediction markets, September 15, 2026. Secondary; single-outlet exclusive.
Platform documents (all countries): Polymarket Help Center: Geographic restrictions (updated August 14, 2026), Polymarket developer docs: Geoblock (undated), Kalshi Member Agreement (undated; fetched September 24, 2026) and Kalshi Help Center: trading from outside the US (updated March 20, 2026).
PolyKal is an independent research tool. We are not affiliated with, endorsed by, or operated by Polymarket or Kalshi. We report each platform's published rules and public regulator, court and police actions in Japan; we don't say whether trading is legal for you, and we don't help anyone get around a platform's restrictions. Last reviewed September 26, 2026. Not legal or financial advice.
Know of a newer rule, order or court decision for Japan? Email [email protected] with a link to it.