My USDT got frozen — who froze it, and can it be undone?
A USDT freeze is executed by the issuer, Tether, inside the token contract: the address goes on the contract's blacklist, usually at the request of law enforcement or a regulator. Frozen USDT cannot leave the address; other assets there (TRX, ETH) are unaffected. Step one is confirming it really happened — with a read-only on-chain lookup, not by trusting "support staff" or an "unfreezing service": OceanAlt's free check reads the issuer contract directly and shows "Tether USDT freeze list: isBlackListed = true" when an address truly is frozen. Unfreezing goes only through Tether's official process; every paid unfreezing service is a second scam.
Who can freeze, and why it lands on you
Both the USDT and USDC contracts have a built-in blacklist the issuer can add any address to. Triggers are typically law-enforcement requests, stolen-fund tracing, or sanctions links. A freeze is not a sanction: many frozen addresses appear on no government list, and vice versa — the two layers need separate checks.
The most common way to get caught: you accept a payment whose upstream is dirty (stolen or scam funds), the whole address gets frozen afterwards, and your clean money is stuck with it. Screening the payer before you accept costs far less than appealing after.
How to confirm the freeze is real
Paste the address into oceanalt.com/en/check: a real freeze shows up as a "Tether USDT freeze list" item, backed by a read-only call to the USDT contract (isBlackListed = true). That is the same on-chain fact you would get checking the contract on a block explorer yourself — no private database involved, so you can verify it independently.
A frozen balance inside an exchange account is a different thing: that is the platform's own risk action, not on chain, and goes through the platform's compliance or support process.
Can it be undone, and how to avoid it
The only route to an on-chain unfreeze is Tether itself (its site lists law-enforcement and compliance contacts); expect to document the source of funds, wait months, and depend on the case. Anyone who approaches you offering paid unfreezing is running a scam — freeze lists are public, and scammers use them to find victims with precision.
Prevention comes down to three habits: screen the payer's address (free) before large receipts; put long-term counterparties on a watchlist so a status change pushes to you; and keep separate addresses for separate purposes, so one bad inbound payment can't freeze everything you hold.
Where to start: free address check · API docs · watch an address
Boundary of everything above: a screening "clear" only means no match in the data held, never a safety guarantee; this page is not legal or compliance advice.