If you forget your password, please follow these steps to reset it:
Visit the Password Reset page.
Enter the email address associated to your Coinbase account and select RESET PASSWORD to receive an email.
From the email, select Reset password to open a window where you'll enter a new password. If you run into trouble, please see this article for help.
Enter your new password in the Choose A Password and Confirm Password fields, then select UPDATE PASSWORD.
You can now sign in with your new password.