G Suite: How to Import Messages into Gmail

Detailed instructions can also be found on Google's support site.

Log in to Gmail for your G Suite account.
Click on the Gear Icon in the top right.
Select Settings.
Select Accounts.
Under 'Check mail from other accounts,' click 'Add a mail account'
Enter a label for the address. You need to provide a slightly different email address, as G Suite won't let you use the same address you are converting. This is only a label, you can use any address, such as john.oldmail@yourdomain.com.
Click Next Step.
Enter your specific connection settings:
- Username: The full email address for your old mailbox.
- Password: The password for your old mailbox.
- POP Server: Select an appropriate server. If you are connecting to an old webmail account with iPage, refer to our Email Client Setup article for the correct settings.
- Port: Select an appropriate port number (SSL recommended). If you are connecting to an old webmail account with iPage, refer to our Email Client Setup article for the correct settings.
- Leave a copy of retrieved messages on the server: Optional.
- Always use a secure connection (SSL) when retrieving mail: Recommended.
- Label incoming messages: Optional.
- Archive incoming messages: Optional.
Click Add Account.