Twin Tunnels Reef

Best months: Jul–Oct

Protected Area

Tulagi Island

Why dive here

With 391+ marine species recorded in the area - including barracuda, blacktip reef sharks, grey reef sharks, humpback whales and orcas - Twin Tunnels Reef offers some of Iron Bottom Sound's richest reef diving. Water ranges 29-31°C, warmest January, April, December.

Best timeJul–Oct

WetsuitA 3mm shorty or thin full wetsuit

Marine lifeBarracuda, Blacktip Reef Sharks, Grey Reef Sharks, Humpback Whales and Orcas · 391+ species recorded

Water29-31°C · warmest January, April, December

CharacterReef dive

StandoutExceptional marine biodiversity

Twin Tunnels is one of those sites we always make a point of revisiting. It's a proper pinnacle reef, dropping straight down from 15m to a sandy bottom somewhere beyond recreational limits. What makes it special are the two vertical shafts that cut through the reef top. Dropping into one, you immediately feel the temperature dip and hear the subtle rush of water. Sunlight filters down, illuminating schools of tiny silversides shimmering like glitter. We often find ourselves just hovering in the shafts, watching the light play on the walls. They open into a larger chamber at 36m, and this is where the real action often happens. It's a natural meeting point for predator and prey, so keep an eye out for talang queenfish patrolling the current, and we’ve spotted black triggerfish flitting about. Outside the chamber, the reef is just bursting with colour – soft corals swaying, and we’ve seen multiple species of anemonefish sharing the same anemone, which is always a treat. Our favourite moment is usually exiting the tunnel and looking back up at the blue, often catching a fleeting glimpse of something larger in the distance. It’s a site that rewards careful exploration, great for those who enjoy a bit of overhead environment combined with vibrant reef life.