Tumon Bay Marine Preserve – Gun Beach & Tumon Bay

12m Max

15-30m Vis

shore

Site Overview

Tumon Bay Marine Preserve is a protected shallow coral reef area within Guam's main tourist district, offering some of the most accessible and family-friendly diving and snorkelling on the island. The marine preserve status has ensured healthy coral populations and abundant fish life, with butterflyfish, parrotfish, and anemonefish thriving among the coral gardens. The shallow depth of 2 to 12 metres and calm protected conditions make this an ideal site for Open Water training dives, refresher dives, and snorkelling excursions. Green sea turtles are regularly encountered feeding on the reef, providing memorable encounters for divers and snorkellers alike. The coral formations include both hard and soft corals, with staghorn thickets, brain corals, and colourful soft coral colonies creating a diverse underwater landscape. The site is directly accessible from Tumon Beach, making it possible to walk from your hotel room to the dive entry in minutes. Multiple dive operators in the Tumon area use this site for certification courses and introductory dives, taking advantage of the reliable conditions and abundant marine life. The marine preserve designation has been instrumental in maintaining fish biomass levels significantly higher than adjacent unprotected reef areas, demonstrating the effectiveness of no-take marine reserves in tropical island environments. The shallow coral gardens also provide essential nursery habitat for numerous reef fish species that later populate the deeper reef systems surrounding Guam. Regular scientific monitoring by marine biologists confirms the ongoing health and productivity of this protected ecosystem.

Dive Briefing

"Enter from the Tumon Beach shore access and swim out to the coral gardens, which begin at approximately 3 to 5 metres depth. The reef slopes gently from the shore to the deeper sections, with coral bommies and sandy channels creating varied habitat. Work your way along the reef, noting the butterflyfish, parrotfish, and anemonefish among the coral formations. Green sea turtles are regularly seen grazing on the reef and should be observed from a respectful distance. The shallow depth allows for extended bottom times of 50 minutes or more. Maintain excellent buoyancy to protect the coral formations and avoid fire coral contact. The site is excellent for practising skills and building confidence in new divers. Exit via the same shore entry, being careful of swimmers and snorkellers in the popular bay area. The shallow reef top features numerous cleaning stations where smaller wrasses and gobies remove parasites from larger fish including groupers and parrotfish. These cleaning interactions provide fascinating observation opportunities for patient divers who hover motionless near the stations."