This dive site, Tumon Bay, is Guam's most popular and accessible underwater destination, situated along a 1.5-mile stretch of sandy beach fringed by resorts. It uniquely offers a shallow, calm lagoon (approximately 1 meter deep) that transitions into a dramatic reef drop-off, plunging to depths of 30 meters. Navigation typically involves exploring the shallow lagoon close to shore, then venturing towards the reef edge where the topography changes significantly, revealing a vibrant wall-like structure.
The reef ecosystem here is teeming with a diverse array of marine life typical of Micronesian waters. Divers and snorkelers can expect to encounter numerous species of colorful reef fish, including parrotfish, butterflyfish, damselfish, and surgeonfish. The corals, both hard and soft, form intricate structures, providing habitat for anemones with their resident clownfish, various crustaceans, and mollusks. Occasional sightings of sea turtles, small reef sharks, and eagle rays might occur closer to the drop-off.
Tumon Bay is suitable for diving and snorkeling year-round, though the drier months (December to June) often offer the best visibility. Its dual nature makes it an excellent choice for groups with mixed experience levels, from first-time snorkelers in the lagoon to experienced divers exploring the deeper reef. Freedivers will find ample space to practice in the lagoon and challenge themselves on the drop-off. Due to its popularity, it can be quite busy, especially on weekends and holidays, so early morning dives are recommended for a quieter experience.
