Diving Guide to Double Reef

About Double Reef

Double Reef is one of the rarest and most pristine dive environments in Guam, featuring a double-barrier reef system that creates distinct inner and outer diving experiences. The outer wall presents sheer drops plunging into deep Pacific water, with schooling jacks, tuna, grey reef sharks, and possible manta ray encounters in consistently excellent visibility. The inner lagoon provides calm, protected macro diving with seahorses, pipefish, nudibranchs, and juvenile fish in a serene environment sheltered from ocean swells. This unique geological formation, with two parallel reef crests separated by a sandy channel, is extremely rare globally and provides a remarkable contrast between adrenaline-pumping pelagic action and gentle macro exploration. Double Reef is less frequently dived than other Guam sites due to its northwestern location and limited operator access, which has helped preserve the pristine condition of the coral formations. The site appeals to experienced divers seeking variety and exclusivity, and to underwater photographers who can capture both wide-angle and macro subjects on a single dive trip.

Highlights

• ✓Rare double-barrier reef system with distinct inner lagoon and outer wall environments
• ✓Outer wall with sheer drops and schooling jacks, tuna, and grey reef sharks
• ✓Inner lagoon macro paradise with seahorses, pipefish, and nudibranchs
• ✓Pristine coral formations preserved by limited diving pressure
• ✓Possible manta ray encounters on the outer reef

Getting There

Double Reef is located on the northwestern coast of Guam, accessible exclusively by boat from operators based in Tumon Bay or Tamuning. The boat ride takes approximately 15 to 20 minutes from Tumon. Due to its relative remoteness and limited operator schedules, trips to Double Reef are less frequent than other sites and advance booking is recommended. The site is best dived in the morning when seas are calmest. Some operators combine Double Reef with nearby Ritidian Point dives for a full-day northern diving experience.