Tumon Bay sits on Guam's western shore along the Philippine Sea and is the island's most accessible area for shore-based diving and snorkelling. All three sites in the database are reached directly from the beach, and skill requirements are pitched at beginners. The bay combines shallow reef flats and seagrass with a drop-off at Tumon Bay itself, while Gun Beach extends into deeper reef territory. Species recorded here include emperor angelfish, bluefin trevally, leopard wrasse, and reticulated butterflyfish. Water stays warm year-round, making it a practical year-round destination.
Monthly water temperature across Tumon Bay's sites, from satellite sea-surface data corrected for depth. The band shows the site-to-site spread.
Water temperature in Tumon Bay is warm throughout the year, sitting a little cooler in the early months and warming through mid-year. Conditions in the sheltered bay are generally mild, making it a reliable choice regardless of season.
Water temperature around Tumon Bay ranges from about 28°C in January to 30°C in July, based on satellite sea-temperature data for its dive sites.
With water around 28–30°C, a rash guard or 3mm shorty works in Tumon Bay year-round.
Fin maps 3 sites in Tumon Bay (1 scuba diving sites and 2 snorkelling spots).
