Gate-side in the Main Terminal, ABC Stores is the quick errand stop between security and boarding at GUM. It sits airside in the Main concourse, so you hit it after passport control, not in check-in. Think mini convenience store plus souvenir stand: snacks, bottled drinks, sunscreen, neck pillows, and Guam-branded mugs and T‑shirts in one compact space.
Prices run higher than downtown Guam, with snacks and drinks often a dollar or two above city supermarkets, but still less painful than many mainland US airports. You’ll find single-serve chips, instant noodles, spam musubi–style bites when stocked, and plenty of candy bags for the flight. Drinks cover canned coffee, sodas, and basic bottled water in the usual 500 ml and 1 L sizes.
For last-minute Guam gifts, ABC Stores lines the walls with logo shirts in common sizes, keychains, magnets, and small bags of local-style cookies. Expect mostly mass-market brands rather than artisan items, but it beats backtracking to landside shops. Toiletries run from travel-size toothpaste and toothbrush kits to basic painkillers and motion sickness tablets, handy if you forgot something at home.
Lines spike before late-night departures when several flights out of the Main Terminal board within 60–90 minutes of each other, so factor in a 5–10 minute wait at the single checkout. Credit cards from major networks usually work without issue. One last tip: grab water and any instant noodles here before heading to the gate, as vending options thin out toward the far end of the concourse.