Originally Posted by
quintic
So the border control is at GUM airport? How about luggage?
1. Go through US CBP immigration. Proceed downstairs.
2. Go through Guam customs with carry-on. (Fill out Guam customs form ahead of time.)
3. Exit landside, go back upstairs for TSA security check.
4. Proceed to gate.
Guam is small enough an operation, and that hour is quiet both for arrival and departure. And since GUM-YAP is international they have to pull your bag if you don't show. All these mean they know who's coming and going. So unless you disappear into the bathroom for a prolonged period of time, you should be fine.