After swimming at the beach, my brother and I discovered a place called VeryBerry in Tumon.
It's kind of like Yogurt Land and Menchi's in Honolulu. They have frozen yogurt and customers can pick their own toppings. They also make fruit smoothies and milkshakes.
The seating area isn't so comfy, but their hours are convenient and they have Wi-Fi access. The store is open from 7 a.m. to 11 p.m., which is perfect for studying late at night or grabbing a cold treat after a movie.