Are sei1 and 0x addresses the same account or different accounts?

Same account. Both formats derive from the same private key — sei1 uses bech32 encoding, 0x uses hex with EIP-55 checksum encoding. The underlying 20-byte address is identical. Sending SEI to either format reaches the same account; signing with the private key works for either.

Do I need to 'convert' my sei1 address to a 0x address?

No conversion needed cryptographically — the formats are alternate displays of the same address bytes. What you may need is to update third-party services (CEXs, dApps) to use your 0x address, because the post-SIP-3 standard is 0x.

Will the sei1 format ever stop working?

The sei1 format remains a valid representation of your account on the Sei chain. The chain still accepts transactions signed with private keys whose addresses are presented in either format. Post-SIP-3 the 0x format is the primary; sei1 is legacy but functional.

I see a sei1 address in my old wallet that doesn't match my 0x address. What happened?

Most likely your old wallet derived multiple accounts from your seed, and the sei1 you're seeing is a different account index. Check Sei Wallet's Accounts list. Or use seitrace.com to confirm whether they share state.

What does the address association tool actually do?

It walks through your seed-derived addresses (both formats), verifies they're the same underlying account, and surfaces any balances at legacy sei1 addresses that haven't been seen by the post-SIP-3 0x display. For most users there's nothing to associate — the tool is for edge cases.

How SIP-3 Changed Sei Addresses

What SIP-3 actually is

SIP-3 stands for Sei Improvement Proposal 3 — the chain-governance proposal that retired Sei's Cosmos-native components and made the chain EVM-only. Approved by community vote in May 2025. Transition completed in early 2026, with Cosmos features fully deprecated by April 6-8, 2026.

What SIP-3 retired: CosmWasm smart contracts, IBC inbound transfers, native Sei oracle, bech32 (sei1...) addresses as the primary format, Cosmos-format keys for new accounts.

What SIP-3 kept and made primary: EVM compatibility, 0x-prefix hex addresses, ECDSA secp256k1 signing, all on-chain history.

The two address formats

Before SIP-3, Sei looked like a Cosmos chain. Cosmos chains encode addresses using bech32:

sei1qxy2kgdygjrsqtzq2n0yrf2493p83kkfjhx0wlh

The sei1 prefix identifies the chain. The rest is a checksummed encoding of the address bytes.

After SIP-3, Sei looks like an Ethereum-compatible chain. EVM addresses are hex:

0x6Bf7c1B0FF7FF2c4dEBa8DD3cFd1a9d7B82F5A35

The 0x prefix is the standard Ethereum hex prefix. Mixed-case casing is EIP-55 checksum encoding.

These two formats look completely different. They appear to identify different accounts. They don't.

Same private key, different formats

Both sei1... and 0x... addresses on Sei are derived from the same private key. Take the secp256k1 public key, hash with Keccak-256, take the last 20 bytes. The 20 bytes are then encoded — bech32 with sei1 prefix for Cosmos display, or hex with 0x prefix for EVM display.

Same 20 bytes. Two different printings.

What this means in practice:

If your seed phrase derives sei1abc...xyz, it also derives the equivalent 0x... address
Sending SEI to either format goes to the same account
Signing transactions works regardless of which format you reference
A wallet showing only one format is missing half the picture

Sei Wallet's address handling shows both formats by default.

Why SIP-3 made this change

Sei chose to focus on EVM compatibility because EVM tooling, developer ecosystems, and dApp portability are the dominant network effect in DeFi. Specific arguments: developer reach (largest pool), tooling (Hardhat, Foundry, MetaMask, OpenZeppelin), cross-chain bridges (Wormhole, LayerZero, Circle CCTP), trading infrastructure (EVM-aware).

The trade-off: Sei loses some Cosmos-multi-chain elegance and the deep CosmWasm ecosystem. The community vote concluded that the EVM-focus trade-off was net-positive.

What if I have funds at a sei1 address

Funds are still yours. Your seed phrase derives that address, you sign for it, you control it. The address association tool inside Sei Wallet walks through both cases. For full migration step-by-step, see /migrate-cosmos-to-evm.

Reading addresses on the explorer

Sei block explorers — seitrace.com and seistream.app — accept both formats. Inside the account page, the explorer shows the 0x address as primary with the sei1 form as alternate display.

Forward-looking: what to use going forward

Use 0x... for everything new.
Reference sei1... only for legacy reasons.
Trust the chain over the wallet display. seitrace.com is the source of truth.
One private key, one account, two display formats.

How SIP-3 changed Sei address handling: sei1 vs 0x