Hi there
I’d be happy to help you keep your GoPhone account active whilst travelling! I would recommend that you check that you’re able to access your online myAT&T account now, as to keep the account active, you will be required to refill within 60 days of your plan expiring. Click here to manage your GoPhone account. As the method of gaining access to your myAT&T account if you have forgotten any of the details requires receiving a temporary PIN via SMS, it is important that you can ensure you can access the account now, as you will be unable to receive that SMS while travelling (unless roaming in Canada/Mexico).
I hope this helps!
Charise