Chuuk Lagoon is an atoll ringed with reefs and containing a number of populated islands. It is the main population centre of the state of Chuuk in the Federated States of Micronesia.
The Chuuk Lagoon is a major scuba diving destination for divers interested in wreck diving. Chuuk Lagoon was a port for the Japanese fleet in World War II and was attacked by the American navy in Operation Hailstorm on February 16th 1944. The lagoon contains the wrecks of over thirty naval ships and 250 aircraft. Many of the ships still have cargo including medical supplies, armaments, trucks and mines. The most commonly dived wrecks are the:
- Heian Maru, a 530 ft (162m) long ship in 110ft (34m) of water
- San Franciso Maru, a 385 ft (117m) long cargo boat with the stern in 210 ft (64m) and the front mast in 90 ft (27m).
- Fujikawa Maru, a 437 ft (133m) long freighter upright on the sea floor.
- Nippo Maru, a 353 ft (108m) long freighter sitting upright in between 50 ft (15m) to 150 ft (46m) of water.
- Upside Down Zero, an Allied attack fighter plane in 60 ft (18m) of water.
- Betty Bomber, an Allied attack fighter plane in 50 ft (15m) of water.