Twin Tunnels

The site is a seamount rather than a fringing reef, sitting in the middle of the channel between Guadalcanal and the Florida Islands, and the dive begins on its top at around 12 m. Two large holes open in the reef top; they are the mouths of two ancient lava tubes. The current up here is mild, so there is time to look into both, sort out buoyancy and lights, and pick one before starting down.

Inside, the tube takes you to 35 m. The light does the work on the way down — the circle of blue above you shrinks the deeper you drop — and the tunnel finishes by putting you out through a cave full of crayfish, onto the outside of the pinnacle with the reef falling away to around 45 m beneath your fins and the deepest part of the site running to 60 m.

From there it is a controlled drift back along the reef in the mild current, which is where most of the fish are: schools of fusiliers, grey reef sharks off the structure, kingfish and tuna passing through, and manta rays and trevally as well. Closer in, cuttlefish, mantis shrimp and octopus work the reef, as many as nine species of anemonefish hold in their anemones, and pygmy seahorses are here for divers who take the time to look.