Coincheck review: how Japan’s first IOST exchange holds up

Verdict: a trustworthy yen on-ramp with a shallow pool

We score Coincheck 7.5 out of 10 for IOST buyers. It is registered with Japan’s Financial Services Agency, it sits inside a Nasdaq-listed group, and its IOST/JPY order book charges just 0.05% for makers and 0.10% for takers. It also passes on the IOST 3.0 airdrop to holders, which few venues anywhere do so clearly.

The weak spot is depth. Coincheck’s IOST/JPY book is small, and the two biggest IOST markets in the world, Binance and Upbit, often trade on the order of a hundred times more IOST per day. For a ¥10,000 or ¥100,000 purchase that hardly matters. For a large order it does, because you will move the price. The other trap is the app: its simplest buy button sends you to the 販売所, where the spread can cost far more than the order-book fee.

Coincheck at a glance

Coincheck started in 2012, launched its exchange in 2014 and became famous twice: first as one of Japan’s biggest crypto apps, then for the 2018 NEM hack. Monex Group bought it after the hack, and the group company Coincheck Group N.V. listed on Nasdaq on 11 December 2024 through a SPAC merger. That listing means more public disclosure than most Asian exchanges offer. The FSA register names IOST among the assets Coincheck handles.

The IOST/JPY market on Coincheck

Coincheck was the first Japanese exchange to list IOST, with trading from 8 September 2020. That early listing helped make Japan one of IOST’s strongest communities, a story we cover on our IOST in Japan page. IOST is on the JVCEA Green List, and four FSA-registered exchanges handle it: Coincheck, OKJ, BitTrade and Binance Japan.

You can buy IOST in two places. The 取引所 is a real order book where you trade with other users at prices you can see. The 販売所 is a counter where Coincheck itself is the other side and builds its margin into the price. For IOST the order book is almost always the better deal, though it lives mainly on the web version rather than the app’s simple flow.

Liquidity is thin in relative terms. Coincheck and OKJ run Japan’s two active IOST/JPY books, and both are tiny next to Korea’s KRW market. In our checks the gap between the best bid and the best ask on Coincheck was around one percent, several times wider than on Binance. Check the live IOST price before you trade, and use limit orders so you control the price you pay.

A Shibuya exchange for a Japan-loved coin

Coincheck’s registered office is in Shibuya Sakura Stage, by Shibuya station. Japan is often described by the project as IOST’s largest community, yet most of the world’s IOST volume now trades on Korea’s Upbit and on Binance.

Fees and spreads

The order-book fee for IOST/JPY is 0.05% maker and 0.10% taker. Most other pairs on Coincheck’s 取引所 are free, so IOST is one of the few coins with a charge, but it is still cheap. The 販売所 charges no separate fee. Instead, you pay the spread, which Coincheck describes as roughly 0.1% to 5.0% of the reference price, and 1.7% to 7.0% for some coins when markets are volatile.

Here is a worked example. If you buy ¥100,000 of IOST on the order book as a taker, the fee is ¥100. If you buy the same amount on the 販売所 and the spread happens to be 3%, you lose about ¥3,000 the moment you buy, and you pay a spread again when you sell. That gap is the single most important cost decision on Coincheck.

Deposits, withdrawals and the memo

Coincheck supports IOST on the IOST mainnet (L1) only. We found no support for the BEP-20 IOST token on BNB Chain, so do not send BEP-20 IOST to a Coincheck address. Our IOST 3.0 guide explains why there are now two versions of the token.

Every IOST deposit to Coincheck needs a memo, because the exchange uses one shared IOST account and tells users apart by that memo. Coincheck says plainly that once a transfer has a transaction ID it cannot cancel, redo or refund it, memo mistakes included. If a deposit has not arrived, you contact the receiving side with your transaction details. Our guide to sending IOST walks through test transfers and what to do when a memo is missing.

Withdrawals cost 1 IOST according to Coincheck’s FAQ, and transfers between Coincheck users are free. Moving 10,000 IOST to your own IOST wallet would therefore cost 1 IOST. Crypto deposits are free, as are yen deposits by bank transfer; yen withdrawals cost ¥407. Around the go-iost v4.0.0 upgrade in October 2026, exchanges briefly paused IOST transfers, so check Coincheck’s notices before you move coins.

Memo first, send second!

The IOST 3.0 airdrop and lending

Coincheck is one of the clearest exchanges for the IOST 3.0 airdrop. It used the snapshot of 15 March 2025 at 09:00 JST and pays its share in 8 rounds, one every six months. Coincheck’s FAQ counts IOST held in your account, IOST in a pending lending application or a lending account, and IOST in Coincheck Tsumitate. Accounts that are being opened, closed or frozen are excluded, and the FAQ excludes coins that are actively lent out, so read it before you lock IOST into a lending term near a payout. Our IOST airdrop guide covers the wider programme.

The credit arrives automatically. Coincheck never asks you to connect a wallet or send IOST first, so any message that does is a scam. History shows Coincheck is cautious here: in September 2021 it declined the Donnie Finance (DON) airdrop for IOST holders, citing doubts about DON’s liquidity and technical safety, while OKCoin Japan supported it.

1. Jan 2018NEM hackAbout 523M XEM stolen from a hot wallet; holders refunded in yen in March.
2. Apr 2018Monex takes overMonex Group buys 100% of Coincheck.
3. Jan 2019FSA registrationRegistered as 関東財務局長 第00014号.
4. Sep 2020IOST listedJapan’s first IOST listing, trading from 8 September.
5. Sep 2021DON airdrop declinedCoincheck skipped the Donnie Finance round over liquidity and safety concerns.
6. Dec 2024Nasdaq listingCoincheck Group N.V. starts trading as CNCK.
7. Oct 2025Airdrop round 1First of eight IOST 3.0 payouts, paid 30 October.
8. Oct 2026Airdrop round 3Third payout on 15 October after round 2 on 9 April.

Coincheck also runs 貸暗号資産, a lending service for the crypto it handles, with terms of 14, 30, 90, 180 or 365 days and rates of up to 5.0% a year. The IOST rate is shown only after login, and we could not confirm it. We found no IOST staking product on Coincheck. If staking is what you want, our IOST staking guide explains node voting and the exchange options in Japan. Remember that lent coins are held by Coincheck, so this is a credit risk, not a protocol reward.

Regulation and safety record

On 26 January 2018 attackers stole about 523 million XEM, worth roughly ¥58 billion, from Coincheck’s hot wallet. Coincheck refunded about ¥46.3 billion in yen to around 260,000 holders in March 2018, the FSA issued business-improvement orders, and Monex bought the company in April. In June 2020 a hijacked domain-registrar account exposed personal data of about 200 users, with no asset loss reported. We found no incident in 2025 or 2026.

Japanese law now does a lot of the safety work. Registered exchanges must keep the bulk of customer crypto offline (at least 95% in cold wallets), hold customer yen in segregated trust, and back any hot-wallet balance with their own crypto. Coincheck does not publish a Merkle-tree proof of reserves; its segregation is audited under Japanese rules instead. Our Is IOST safe? page covers the risks of the token itself, which no exchange can remove.

How to buy IOST on Coincheck

1. Open and verify an account

   Sign up with a Japanese address and complete smartphone eKYC with Japanese ID. Accounts are for Japanese residents only.

2. Deposit yen

   Bank transfer is free apart from your bank’s fee. Konbini and quick deposits start at ¥770.

3. Switch to the 取引所

   Open the IOST/JPY order book on the web version and place a limit order. Avoid the app’s simple 販売所 button for IOST.

4. Decide where to keep it

   Leave it on Coincheck to receive airdrop rounds, or withdraw on the IOST mainnet with the correct memo. See how to buy IOST for the general flow.

Pros and cons

Not in Japan?

Coincheck accepts only Japanese residents, and CEX.IO does not serve Japan at all. If you live elsewhere in Asia, you can buy crypto with a card on CEX.IO, an exchange running since 2013, then move it to an exchange that lists IOST.

Get your first crypto

CEX.IO does not accept residents of Japan. In Japan, buy IOST through an exchange registered with the Financial Services Agency (FSA).

Alternatives in Japan

If you live in Japan, stick with an FSA-registered exchange. Overseas platforms such as Binance.com, Bybit, MEXC and KuCoin have received FSA warnings for serving Japanese residents without registration. Among registered venues, OKJ is Coincheck’s closest rival for IOST, with a similar-sized or slightly busier book and staking products. BitTrade lists IOST but sees very little trading. Binance Japan lists IOST, though we could not confirm whether it offers an order book or only a convert screen. bitFlyer, bitbank and GMO Coin do not list IOST, and BITPOINT and CoinTrade dropped it in 2026.

For the full side-by-side, including Korean and global venues, see our IOST exchanges comparison. If you are not in Japan, the Upbit review covers Korea’s KRW market. For the network itself, our IOST explorer guide shows how to confirm a withdrawal arrived. Prices swing hard: IOST has traded more than 99% below its January 2018 high, so only buy what you can afford to lose.