How to Migrate SEI From Cosmos to EVM Without Losing Your Funds

In early 2026, SEI, a high-performance blockchain network, completed a major architectural overhaul. It shut down one of the two technical systems it used to run on, called Cosmos, and consolidated everything onto a single standard called EVM. For most people using SEI on centralized exchanges, this happened automatically. For self-custody wallet users, i.e.,  people holding their own keys, it requires a manual step.
 

This article explains what happened, why it happened, what Tangem did to ensure none of our users were left behind, and how to migrate your SEI if you haven't already.

What is SEI, and why did it run on two environments?

SEI is a Layer 1 blockchain, a standalone network, like Ethereum or Solana, with its own rules, validators, and infrastructure. It launched in 2023 with an unusual design: it ran two separate technical environments simultaneously.

One side used EVM. The other used Cosmos. To understand why that matters and why dropping one of them is a big deal, it helps to know what each one actually is.

SEI originally supported both because the idea at the time was appealing: give developers and users the flexibility of two ecosystems in one place. In practice, maintaining both proved an engineering liability. Two systems meant double the complexity, double the maintenance, and a fractured user experience, with some wallets only working on one side.

Why did SEI abandon Cosmos?

In May 2025, the SEI community voted on a governance proposal called SIP-3. The vote approved deprecating the entire Cosmos layer (CosmWasm smart contracts, IBC transfers, native Cosmos transactions) and transitioning SEI to an EVM-only chain.
 

EVM won the developer gravity war; the tooling, wallets, bridges, and developer talent all center on EVM. Maintaining a parallel Cosmos environment added complexity without providing enough value to justify it.

The transition rolled out in three phases across early 2026:

1. Version 6.3 (January 2026): Enabled staking through EVM, removing one of the last dependencies on the Cosmos layer.
    
2. Version 6.4 (February 2026): Disabled inbound IBC transfers (the protocol that lets Cosmos-based assets move between chains), cutting the connection to the broader Cosmos ecosystem.
    
3. Version 6.5 (March 2026): Removed SEI's native oracle from the codebase, replacing it with established providers including Chainlink, API3, and Pyth.
    
4. Final migration window (April 6–8, 2026): The full Cosmos stack was switched off. SEI became an EVM-only chain.

The target on the other side of all this: a chain capable of processing more than 200,000 transactions per second, with sub-400ms transaction finality. 

What Tangem did to help users migrate

When SEI published the SIP-3 roadmap, Tangem didn't wait. The day the direction became clear, we started treating it as a deadline we owned.
 

As soon as the SIP-3 timeline became clear, we began building EVM support for SEI on our side. We stayed in close contact with the SEI team, tracked their migration documentation as it evolved, and stress-tested our implementation throughout the process.
 

During this work, we identified a specific problem that was easy to overlook at the scale of a network-wide migration: some Tangem cards had been set up only for SEI's Cosmos side. They had no EVM address at all.
 

For those users, the standard migration flow simply wouldn't work. We flagged this directly to the SEI team. They heard us out and updated the migration flow to cover these edge cases.
 

Before the Tangem upgrade went live, we ran the entire migration end-to-end on a real wallet, tracing the exact path a user would take.

How to migrate your SEI 

The SEI team published an official migration guide. What follows is a plain-English walkthrough of what to expect when you go through it.

1. Connect via WalletConnect: On the SEI migration site, link your Tangem Wallet using the WalletConnect option in the app.
    
2. Fund your new SEI EVM address: Your new EVM address needs a small top-up from an external source before the migration can proceed. This covers the network fee for the migration transaction.
   
   This is the most hands-on step of the process. You'll need to send a small amount of SEI to your new EVM address from another wallet or exchange. 
    
3. Ignore the temporary address: During the migration, the flow routes your old Cosmos balance through an intermediary address before it arrives in your new EVM wallet. This is normal; it's how the protocol bridges between the two environments.

Once the process is complete, that intermediary address is irrelevant. You can forget it exists.

What we’ve learned from this migration

Tangem runs a continuous monitoring process that tracks changes across every network we support. We caught the SEI migration when the roadmap dropped. That lead time is the difference between a smooth rollout and a scramble. It's not glamorous work, but it keeps earning its place.
 

Some problems still get solved by talking to people. The fix for Cosmos-only Tangem cards didn't come from a script or an automated monitoring tool. It came from a direct conversation with the SEI team. Even now, with AI in everything, certain problems still get solved by two teams actually talking to each other.