Piti Channel – Piti Bay & Western Shoals

Site Overview

Piti Channel is a boat-accessed drift dive that funnels divers through a reef passage patrolled by larger pelagic species including grey reef sharks, eagle rays, and substantial grouper. The channel current carries nutrient-rich water that attracts an impressive array of predators and schooling fish, making it one of the best sites on Guam for observing large marine animals in their natural environment. Grey reef sharks are regularly encountered cruising the channel floor at depths of 20 to 30 metres, while eagle rays glide overhead in the mid-water column. Large groupers inhabit the deeper sections of the channel, often resting near the reef wall or patrolling the sandy floor. Schools of barracuda and trevally form along the current edge, creating dramatic formations that provide stunning wide-angle photography opportunities. The channel walls are covered in soft corals and gorgonians that sway in the current, adding colour and movement to the pelagic spectacle. This is an advanced dive that requires drift diving experience and comfort with strong currents, but rewards qualified divers with some of the most exciting big-animal encounters available on Guam. The channel formation funnels deep ocean water across the reef platform, carrying planktonic organisms that sustain the rich filter-feeding communities attached to the channel walls. This nutrient delivery system supports one of the most productive marine ecosystems on the western coast of Guam, attracting pelagic predators from the surrounding open ocean environment.