How to Buy O3 Swap
Every exchange we track that lists O3, what the buy costs, and what it costs to take O3 with you afterwards.
7 of the exchanges we track list O3, and 6 of those accept fiat, so you can buy it without holding crypto first. The cheapest place to place the order is MEXC at $0.50 on a $1,000 market buy. It is also the cheapest once the withdrawal fee is added — $0.50 to buy $1,000 of O3 and move it to your own wallet. O3 moves over 3 networks (Ethereum (ERC20), BNB Smart Chain (BEP20), HECO) — pick the same one on the exchange withdrawal screen and in your wallet. 2 of them have O3 withdrawals paused right now — you can buy there, but you cannot take the coin with you until it reopens.
Networks O3 runs on
Where to buy O3
All-in cost is the trading fee on a $1,000 market buy plus the cheapest fee that exchange charges to withdraw O3. It is the number the exchange’s own “how to buy” page never shows you, and it reorders the table more often than not. The coins column is how many assets each exchange lists in total, from our own sync — not the figure CoinMarketCap prints.
| Exchange | Buy fee on $1,000 | Move it out | All-in cost | Coins listed | Buy |
|---|---|---|---|---|---|
 MEXCReferralPay with Card | $0.500–0.05% taker | FreeEthereum (ERC20) | $0.50 | 9,475 | Visit ↗ |
 HTXPay with Bank, P2P | $2.000.2% taker | $0.0859697.096 O3 · Ethereum (ERC20) | $2.09 | 1,159 | Visit ↗ |
 CoinWPay with Card, Apple/Google Pay, 3rd-party | $1.000.1% taker | $1.451,636.56 O3 · Ethereum (ERC20) | $2.45 | 1,218 | Visit ↗ |
 BitruePay with Card | $2.800.098–0.28% taker | $0.0026563 O3 · Ethereum (ERC20) | $2.80 | 1,784 | Visit ↗ |
 4ECrypto deposit only | — | $0.0017712 O3 · Ethereum (ERC20) | — | 217 | Visit ↗ |
 BitMartPay with Card, P2P, 3rd-party | $1.000.1% taker | withdrawals paused | — | 3,695 | Visit ↗ |
 PionexPay with Card, P2P | $1.000.05–0.1% taker | withdrawals paused | — | 206 | Visit ↗ |
Showing 1–7 of 7 exchanges listing O3
Buying O3 step by step
- Pick a venue from the table. For a coin this size the choice is usually short — 7 exchanges list O3 at all, and the table already shows what you will pay to leave as well as to buy.
- Fund the account. 6 of those exchanges take fiat, 5 of them by card. Card is fastest and dearest; a bank transfer costs a fraction of it. Depositing a stablecoin you already hold is free on almost every exchange here.
- Place the order. A market order pays the taker fee in the table; a limit order that rests on the book pays the lower maker fee. On a thinly traded coin the spread costs more than either, so a limit order is worth the wait.
- Decide whether to move it. Leaving O3 on the exchange is free but custodial. Moving it to a wallet that supports it costs one withdrawal fee — send a small test amount first, and match the network on both sides.
How to buy O3 — FAQ
Where can I buy O3 Swap?
On 7 exchanges we track: MEXC, HTX, CoinW, Bitrue, 4E and 2 more. The table above has each one with its trading fee, the payment methods it takes and what it charges to withdraw O3.
What is the cheapest way to buy O3?
MEXC, at $0.50 to buy $1,000 of O3 and withdraw it — $0.50 in trading fee plus $0.00 to move it out over Ethereum (ERC20). If you are leaving the coin on the exchange, only the first half applies and a different venue may win. Paying by card adds the card processor's charge on top of both, typically 1.8–4%.
Can I buy O3 with a credit card?
Indirectly, yes. 5 of the exchanges listing O3 accept a card, but the card almost always buys a major asset — USDT, USDC, BTC — which you then swap for O3 on the same exchange. That means two fees: the card charge, then the trading fee in the table.
Do I have to pay a fee to withdraw O3?
Every exchange charges one, as a flat amount of O3 per network rather than a percentage. We do not have a priced figure for all of the venues listing O3 yet — the O3 withdrawal fee page has whatever each exchange publishes.
Is it safe to leave O3 on the exchange?
It is a custody choice, not a safety switch. While the coin sits there the exchange holds the keys: convenient, recoverable if you lose your password, and dependent on the exchange staying solvent and keeping withdrawals open. Moving it to a wallet you control removes that dependency and costs one withdrawal fee. For a trading balance, staying put is reasonable; for a long hold, most people move.
Which network should I use for O3?
O3 is issued on 3 networks and they are not interchangeable — O3 sent over Ethereum (ERC20) will not arrive at an address on BNB Smart Chain (BEP20). Ethereum (ERC20) is the one most exchanges use (5 of them). Withdrawal fees differ per network too, sometimes by an order of magnitude, so the cheapest network is worth checking as well as the cheapest exchange.
Exchange coverage for O3 comes from each exchange’s own deposit and withdrawal endpoints (last sync 2026-08-29 00:53 UTC); trading fees are the published base tier, no volume discount applied (verified 2026-08-28). Exchanges we have a referral arrangement with appear first and are tagged as such — it changes no number in any row. Nothing here is investment advice; see our methodology.