Gmail – Forward email from account that has it blocked

Both of the previous answers relate to a feature that is only available through the Yahoo Mail Plus plan, which now costs money.

If you're willing to pay for Yahoo Mail Plus, which would run you $20 for one year, setting up POP or forwarding, as described in the previous answers, is the way to go.

However, I don't recommend it, as you would be paying for an account you don't really use (and for features that are free in Gmail).

Instead, you can use the Import mail and contacts feature from Gmail. To set it up, go to Settings --> Accounts and Import --> Import mail and contacts.

Trying to do it within the web app will be very painful.

The way I would attack it would be to install an e-mail client that supports IMAP. (Thunderbird, perhaps.) Then set up both accounts in the e-mail client. Then, when they're all synced, use the client to copy all of the messages from one mailbox to the other.

You can delete the client software after that if you don't want to use it.