Twin Tunnels, close to Tulagi, is a coral bombie approximately 120 metres in diameter. The top of the reef is in 12 -16 metres of water and features two tunnels eroded in the edge of the reef descending down to a common cavern exiting to the wall at 35 - 40 metres.
The top of the reef is spectacular in its own right and there is no need to go down to the cave. Many divers enjoy the thrill of going down one or other of the tunnels though.
Due to the currents that pass over this reef it attracts many pelagic fish. Dog Tooth Tuna, Blue Fin Travelly, Spanish Mackerel and Barracuda are often seen here along with the usual suspects: the Grey Reef shark, the White Tip reef shark and the Black Tip reef shark. Strong currents are often present, so stay on or near the bottom. At the end of the dive come back to the centre area of the reef to move out of the current, here you find lots of macros to delight.