For a standard Manta Pacific withdrawal, plan for about three days after its state record is posted, plus time for Ethereum transactions. A withdrawal proof shows that your request exists; it does not, by itself, show that the network’s claim about that state is correct.
This is the key trade-off when comparing Ethereum-to-L2 routes: stronger time for challenges means a longer wait before funds are released. The Manta bridge service is a concrete example of a route where a withdrawal has separate proof and release stages.
A valid proof does not settle the state claim
A withdrawal starts on Manta Pacific, the Layer 2 network, when a contract records a message to send assets back to Ethereum. That record is included in a state root, a short fingerprint of the network’s data, which is posted to Ethereum.
You then submit a proof on Ethereum showing that the withdrawal record belongs under that root. The OP Stack specification describes this as an inclusion proof: it verifies the record matches the claim, while the challenge period gives participants time to dispute whether the claim reflects valid network activity.
The challenge window sets the usual wait
Manta Network has described a three-day challenge period for native withdrawals. After proving, the bridge can release funds only when the relevant state claim clears its challenge window and the final Ethereum transaction succeeds.
For example, if you withdraw USDT, an ERC-20 token standard, from Manta Pacific, your withdrawal record first needs to appear in a posted state root. You prove that record on Ethereum, wait for the root’s challenge window to clear, then finalize the withdrawal. Allow extra time for the root to be posted and for both Ethereum transactions to confirm; Ethereum gas is also needed for those transactions.
There is a wrinkle: L2BEAT’s contract review describes a three-day base period that may be shortened, with a 12-hour minimum, but says the feature appeared only partly deployed. Treat three days as the planning figure, and check the actual period for your withdrawal. If its root is successfully challenged or becomes unusable, the withdrawal may need a new proof and a fresh wait.
Check the timer before choosing a route
When comparing routes, look for the challenge period tied to the withdrawal’s state root, not just a claim that transfers are fast. Manta Network has also described “fast finality,” a separate security process intended to shorten waits; a faster estimate matters only if it applies to the specific withdrawal.
Before signing, confirm the destination address and that you are withdrawing to Ethereum Mainnet; WalletConnect is a way to connect a wallet, not a guarantee that a transaction is correct. The Manta bridge example shows why the proof’s status and the release timer both matter.
Takeaway: a withdrawal proof establishes inclusion; the cleared challenge window allows release.