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How to Bridge Crypto Between Chains

Move tokens from one blockchain to another without an exchange. This guide explains how bridges work, which bridge to use for which route, what it costs, and how to avoid the common mistakes.

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11 min read Updated September 2026 DeFi

In This Guide

01 What is a Crypto Bridge? 02 How Bridges Work 03 Popular Bridges 04 How to Bridge (Step-by-Step) 05 Bridge Safety 06 Fees & Speed Comparison 07 Common Issues 08 FAQ 09 Sources

What is a Crypto Bridge?

A crypto bridge is a protocol that moves tokens from one blockchain to another. Blockchains such as Ethereum, Arbitrum, Base and Polygon are separate networks, each with its own state and transaction history. They cannot read each other's data. Bridging is the mechanism that carries value across that gap.

Without bridges, moving assets between chains would mean selling on one chain, going through an exchange, and buying again on the other. A bridge lets you transfer tokens straight from your wallet, usually in a single transaction that completes in minutes.

Bridges matter because activity is spread across many chains. Layer 2 rollups such as Arbitrum and Base charge lower gas fees than Layer 1 Ethereum, but your assets have to get there first. Whether you want cheaper DeFi, a Layer 2 exchange, or to gather tokens scattered across chains, a bridge is the tool for the job. Ethereum.org keeps an overview of bridge designs and their trade-offs (see Sources).

Cross-Chain Transfers

Move ETH, USDC and other tokens between Ethereum, Arbitrum, Base, Optimism and Polygon, usually in minutes.

Access Lower Fees

Bridge to Layer 2 chains, where a transaction costs a fraction of the same transaction on Ethereum mainnet. Learn about gas fees.

Non-Custodial

Bridge directly from your wallet. No exchange account is needed, and you keep control of your keys throughout.

How Crypto Bridges Work

All bridges solve the same problem: blockchains cannot read each other's state. Each bridge uses a different method to verify that a deposit happened on the source chain before releasing tokens on the destination chain. Knowing the method tells you what you are trusting.

Lock & Mint

The most common design. You deposit (lock) tokens in a smart contract on the source chain. The bridge verifies the deposit and mints the same amount of wrapped tokens on the destination chain. The wrapped tokens are a claim on the locked originals.

For example, when you send ETH from Ethereum to Arbitrum through the canonical Arbitrum bridge, your ETH is held in the Arbitrum bridge contract on Ethereum and the same amount of ETH is credited to your address on Arbitrum. Bridging back reverses the process: the ETH leaves Arbitrum and the original ETH is released on Ethereum (see the Arbitrum docs in Sources).

Burn & Release

The reverse of lock and mint. Wrapped tokens on the destination chain are burned (destroyed), and the originals are released from the lock contract on the source chain. This is how withdrawals from a Layer 2 rollup back to Ethereum work.

Canonical bridges of optimistic rollups (Arbitrum, Optimism, Base) hold withdrawals for a challenge period of about seven days. During that window anyone can submit a fraud proof if the withdrawal is invalid. The delay is a security feature: it ensures that only valid withdrawals are released. The exact window is set by each rollup and published in its docs (see Sources).

Liquidity Pool Bridges

Instead of locking and minting, some bridges keep liquidity pools on several chains. When you deposit tokens on chain A, you receive tokens from the pool on chain B. This is much faster than lock and mint because the user does not wait for the slow canonical path.

Stargate and Across both rely on liquidity provided by third parties, who earn fees from transfers. The trade-off is that these bridges depend on enough liquidity being available on the destination chain: a large transfer can face a worse quote or a wait until liquidity is replenished.

Messaging Protocols

Cross-chain messaging protocols such as LayerZero and Wormhole provide a general communication layer between blockchains. Beyond moving tokens, they can carry arbitrary data and instructions across chains. Bridges built on them use the messaging layer to verify deposits and trigger releases.

LayerZero uses decentralized verifier networks (DVNs) to validate messages. Wormhole relies on a set of guardian nodes that sign attestations of on-chain events. The security of any bridge built on these layers depends on the verifiers or guardians behaving honestly.

Popular Crypto Bridges

The right bridge depends on the chains involved, how fast you need the transfer, and how much security you want. Here are the bridges you are most likely to meet.

Arbitrum Bridge (Official)

The canonical bridge between Ethereum and Arbitrum, run by the rollup itself. Deposits take around 10 to 15 minutes. Withdrawals wait for the challenge period of about seven days. No protocol fee, only gas. It settles on Ethereum, so it carries no extra trust assumptions beyond the rollup itself.

Best for: Large transfers where security matters more than speed.

Base Bridge (Official)

The canonical bridge of Base, the Layer 2 built by Coinbase on the OP Stack. Deposits from Ethereum take around 10 to 15 minutes. Withdrawals wait for the challenge period of about seven days. It supports ETH and most ERC-20 tokens with no protocol fee. Base's docs list the front ends you can use to access it (see Sources).

Best for: Moving assets to Base from Ethereum with maximum security.

Stargate Finance

A liquidity pool bridge built on LayerZero. It connects Ethereum, Arbitrum, Base, Optimism, Polygon, Avalanche, BNB Chain and others; the current list is in the Stargate docs. Transfers usually complete in minutes. Stargate pools liquidity across chains to keep the received amount close to the sent amount.

Best for: Fast multi-chain transfers, especially stablecoins.

Across Protocol

An intent-based bridge. You state what you want to receive on the destination chain, and independent relayers deliver it from their own funds, then get repaid from the source chain after the UMA optimistic oracle verifies the fill. Transfers usually complete within minutes, and the fee is quoted before you confirm.

Best for: Fast, low-cost transfers between major chains.

Wormhole

A cross-chain messaging protocol that connects EVM chains with non-EVM chains such as Solana, Sui and Aptos. A set of guardian nodes validates messages, which supports both token transfers and general data messaging. Portal is the main token bridge built on Wormhole. In February 2022, a bug in the Wormhole Solana contract was exploited for about $325 million, one of the largest bridge incidents on record.

Best for: Bridging between EVM and non-EVM chains (Solana, Sui).

LayerZero

A cross-chain messaging protocol that powers bridge applications including Stargate. Developers build omnichain applications on it, choosing which decentralized verifier networks (DVNs) must confirm a message. The supported chain list is in the LayerZero docs (see Sources).

Best for: Infrastructure layer for developers building cross-chain apps.

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How to Bridge Crypto (Step-by-Step)

The process is similar on most bridges. Here is a walkthrough of a typical bridge interface, using ETH from Ethereum to Arbitrum as the example. Button labels change over time, so follow the meaning of each step rather than the exact wording.

Connect Your Wallet

Open the bridge website from a link in the project's official documentation (for the Arbitrum bridge, the Arbitrum docs) and connect your wallet. MetaMask, Rabby, Coinbase Wallet and WalletConnect work with most bridges. Make sure the wallet is on the source chain, the chain you are sending from.

Select Source and Destination Chains

Choose the chain you are sending from and the chain you are sending to. For our example, select Ethereum as the source and Arbitrum One as the destination. Third-party bridges such as Across or Stargate let you pick from many chain pairs.

Select Token and Amount

Choose the token (ETH, USDC and so on) and enter the amount. The bridge shows the estimated amount you will receive, the fees, and the expected time. Keep enough ETH on the source chain to pay the gas fee for the bridge transaction.

Approve the Token (ERC-20 Only)

If you are bridging an ERC-20 token such as USDC (not native ETH), you first approve the bridge contract to move your tokens. This is a separate on-chain transaction, once per token per bridge. Your wallet asks you to confirm it and lets you set an exact amount instead of an unlimited approval. Prefer the exact amount.

Confirm the Bridge Transaction

Start the transfer and confirm it in your wallet. This sends your tokens to the bridge contract on the source chain and costs a gas fee. Before you confirm, check the destination chain, the token, the amount and the receiving address.

Wait for Confirmation

After the transaction confirms on the source chain, wait for the bridge to process it. Canonical rollup bridges take around 10 to 15 minutes for deposits. Third-party bridges such as Across usually finish within minutes. The bridge interface shows the status. Once it is done, switch your wallet to the destination network to see the tokens.

Bridge Safety: Protect Your Assets

Bridges are among the most attacked pieces of crypto infrastructure because they hold large pools of locked value. The two largest incidents on record are the Ronin bridge exploit of March 2022 (about $625 million) and the Wormhole exploit of February 2022 (about $325 million). Chainalysis publishes yearly figures on funds stolen from bridges and other protocols (see Sources). The habits below reduce your exposure.

Verify the URL

Open bridge websites from a bookmark or from a link in the project's official documentation. Phishing sites copy popular bridge interfaces closely. Check the domain before you connect your wallet. Each project's docs list its official bridge address (see Sources).

Start with a Small Test

Before bridging a large amount, send a small test transfer first and confirm the tokens arrive on the destination chain. It costs an extra gas fee, but it catches a wrong network, a wrong address or a broken interface before real money is at stake.

Prefer Official Bridges

For large transfers, use the canonical rollup bridge (Arbitrum, Optimism, Base) whenever the wait is acceptable. These bridges settle on Ethereum. Third-party bridges are faster but add trust assumptions and their own smart contract risk.

Check Contract Addresses

Before approving a token spend, compare the smart contract address with the one in the bridge's official documentation. A malicious contract can drain your wallet. Use a block explorer such as Etherscan or Arbiscan to check the contract is verified and matches.

Bridge Fees & Speed Comparison

Bridge costs and transfer times depend on the bridge type, the direction of transfer and network congestion. The table below summarises the main routes. Timing and fees are indicative and come from each project's documentation (see Sources); the bridge interface always shows the live quote. Understanding gas fees helps you estimate the total cost.

Bridge	Deposit Time	Withdrawal Time	Protocol Fee	Security Model
Arbitrum Bridge	About 10 to 15 min	About 7 days	Gas only	Ethereum L1
Base Bridge	About 10 to 15 min	About 7 days	Gas only	Ethereum L1
Optimism Bridge	About 10 to 15 min	About 7 days	Gas only	Ethereum L1
Polygon PoS Bridge	Tens of minutes	Up to a few hours	Gas only	PoS validators
Across Protocol	Minutes	Minutes	Quoted per transfer	UMA optimistic oracle
Stargate Finance	Minutes	Minutes	Quoted per transfer	LayerZero DVNs

Note: gas costs move with network congestion. A deposit from Ethereum mainnet costs mainnet gas, which is the largest part of the bill; a Layer 2 transaction costs far less. Check a live gas tracker before you bridge. Third-party protocol fees are charged on top of gas. Weigh the total cost against the yield you expect on the destination chain before moving small amounts.

Common Bridging Issues & Fixes

Bridging usually goes smoothly, but things can go wrong. Here are the most common issues and how to fix them.

Stuck Transaction (Tokens Not Arriving)

The most common issue. Your transaction confirmed on the source chain, but no tokens have appeared on the destination chain. Causes include congestion on the destination chain, a bridge processing delay, or a paused sequencer or relayer.

Fix: check the bridge's status page or its transaction history view, where pending transfers are listed. For canonical rollup bridges, allow the full deposit time (around 10 to 15 minutes). If the transaction is confirmed on the source chain, your funds are safe. If nothing has arrived after an hour, contact the bridge's support through the channel listed in its official docs.

Wrong Network Selected

You bridged to the wrong destination chain (for example, Optimism instead of Arbitrum). This is not fatal: you still have your tokens. You will need to bridge again from that chain to the right one, which costs another fee.

Fix: switch your wallet to the chain you landed on, confirm the tokens arrived, then bridge them to the right chain. A third-party bridge such as Across handles Layer 2 to Layer 2 routes without passing through Ethereum. To prevent it, re-read the destination chain before you confirm.

Insufficient Gas on Destination Chain

Your tokens arrived, but you cannot do anything with them because you have none of the native gas token (ETH on Arbitrum and Base, POL on Polygon) to pay for transactions.

Fix: some bridges offer a gas-on-destination option that delivers a small amount of the native token with your transfer. If you skipped it, withdraw a small amount of the gas token from a centralized exchange directly to your address on the destination chain. Some wallets, such as Rabby, also offer a cross-chain gas top-up.

Reverted Bridge Transaction

The bridge transaction reverted on the source chain, which means it failed before your tokens moved. You lose only the gas fee, not the tokens. Common causes: an approval that is too small, a quote that moved beyond your slippage tolerance (on liquidity pool bridges), or a paused bridge contract.

Fix: read the revert reason on a block explorer. If the approval was too small, approve the token again for the right amount. If slippage caused it, try a smaller amount or wait for liquidity to recover. If the contract is paused, wait for the team's announcement or use another bridge.

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Frequently Asked Questions

Is bridging crypto safe?

Bridging carries risk because bridges hold or lock large amounts of value and rely on smart contracts that can be exploited. Canonical bridges run by the rollup itself (such as the Arbitrum bridge or the OP Stack bridge used by Optimism and Base) are generally the safest option because they settle on Ethereum. Third-party bridges trade some security for speed and convenience. To reduce risk, verify URLs, start with a small test transaction, and stick to well-known bridges with published audits.

How long does bridging take?

It depends on the bridge and direction. Deposits from Ethereum to a Layer 2 such as Arbitrum or Base usually take around 10 to 15 minutes, the time needed for the Ethereum transaction to finalize. Withdrawals back to Ethereum through the canonical bridge wait for a challenge period of about seven days on optimistic rollups. Third-party bridges such as Across or Stargate usually complete in minutes in either direction, because they use liquidity on the destination chain instead of the canonical withdrawal path.

What are the cheapest bridges?

Canonical rollup bridges (Arbitrum, Optimism, Base) charge no protocol fee, only gas, which makes them the cheapest option for deposits. Third-party bridges such as Across and Stargate add a fee that is quoted in their interface before you confirm and that changes with liquidity and demand. Compare quotes from two or three bridges before moving a large amount, and include the gas on both chains in your comparison.

Can I bridge any token between any two chains?

Not always. Each bridge supports a specific set of tokens and chain pairs. Canonical rollup bridges move ETH and most ERC-20 tokens, but only between Ethereum and that one Layer 2. Third-party bridges such as Stargate and Across support widely used tokens (ETH, USDC, USDT, WBTC) across several chains, but smaller tokens may not be listed. If your token is not supported, bridge a major token such as ETH or USDC and swap it on the destination chain with a decentralized exchange (DEX).

What happens if my bridge transaction gets stuck?

First, check the bridge interface or a block explorer for the transaction status. A transfer can look stuck when the destination chain is congested or the bridge is delayed. Most bridges have a status page or support channel. If the transaction is confirmed on the source chain but nothing has arrived, wait at least 30 minutes before troubleshooting. With a canonical bridge, the tokens are safe and arrive once the rollup processes the message. If a third-party bridge cannot complete a transfer, most protocols refund the tokens to your source wallet; the exact rules are in the documentation of each bridge.

Do I need gas on both chains when bridging?

Yes. You need the gas token of the source chain (usually ETH) to pay for the bridge transaction. You also need a small amount of the gas token of the destination chain to do anything with your tokens once they arrive. Some bridges offer a gas-on-destination option that delivers a small amount of the native token together with your transfer. If you arrive on a chain with no gas, you can withdraw a small amount of the gas token from a centralized exchange directly to that chain.

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Put Your Bridged Assets to Work

After bridging your tokens, grow your USDC holdings with Coinstancy. Earn 7.50% APY on USDC with Dollar Savings. Interest accrues every second and is automatically reinvested. No lock-up period, withdraw anytime.

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Sources and further reading

The figures and claims on this page rest on the documents below. Time-sensitive figures (rates, yields, fees, market data) move: check the live value at the source before acting on it.

Ethereum.org, Blockchain bridgesethereum.org
What a bridge is, the main bridge designs (lock and mint, liquidity networks, messaging) and the trust assumptions behind each.
Ethereum.org, Layer 2ethereum.org
How rollups work, why fees are lower on Layer 2 and why withdrawals from optimistic rollups wait for a challenge period.
Arbitrum documentationdocs.arbitrum.io
The canonical Arbitrum bridge, deposit timing and the roughly one-week challenge period for withdrawals to Ethereum.
Optimism documentationdocs.optimism.io
The OP Stack standard bridge used by Optimism and Base, and the fault-proof window for withdrawals.
Base documentationdocs.base.org
Bridging to and from Base, and the bridge front ends Base points users to.
Polygon documentationdocs.polygon.technology
The Polygon PoS bridge, its checkpoint mechanism and typical deposit and withdrawal times.
Across Protocol documentationdocs.across.to
Intent-based bridging, relayers, the UMA optimistic oracle and how Across fees are quoted.
Stargate documentationdocs.stargate.finance
Liquidity pool bridging on top of LayerZero, supported chains and fee parameters.
LayerZero documentationdocs.layerzero.network
Cross-chain messaging and the decentralized verifier network (DVN) model.
Chainalysis, Crypto Crime Reportchainalysis.com
Yearly figures on funds stolen in hacks, including the Ronin (March 2022) and Wormhole (February 2022) bridge exploits.

Last reviewed: September 2026. External links open in a new tab; Coinstancy is not responsible for their content.

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