Coinbase does not provide access to the private keys or JSON file needed for importing their wallet into MetaMask. This means that you can't import a Coinbase account to MetaMask through a private key.
Another way to put this is that Coinbase is a custodial wallet, wherein Coinbase itself retains your private keys. MetaMask is a non-custodial wallet.
Please refer to Coinbase' documentation: https://help.coinbase.com/en/coinbase/privacy-and-security/other/is-a-crypto-address-safe-to-display-publicly
On the other hand, you can import your MetaMask wallet to Coinbase mobile wallet by following these steps:
- Open Coinbase Wallet on your mobile device
- Tap your settings at the bottom
- Tap Connect to Coinbase
- Follow out the remaining steps to connect your accounts
Please contact Coinbase support directly if you have any issues importing.
