Simpson Harbour Wreck Diving

Simpson Harbour is the flooded caldera of an ancient volcano — a perfectly sheltered natural harbour with exceptional visibility and water temperature year-round. The Allied bombing campaigns of 1942-1945 turned it into an unintentional museum of WWII Pacific maritime history. Today, dive operators based in Kokopo and Rabaul run regular trips to the main wrecks.

The most accessible dives include the Manko Maru (a large Japanese transport ship), the Submarine Base (submerged infrastructure with Zero aircraft in shallow water), and the Hakkai Maru. Most wrecks are at recreational depths (15-40 metres), making them suitable for advanced open-water divers. The marine life on the wrecks is exceptional — the artificial reefs support schools of reef fish, large grouper, and occasional reef sharks. A live-aboard dive operation also runs multi-day expeditions covering the more distant wrecks around New Britain.

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A story
During World War II, Rabaul was the largest Japanese military base in the South Pacific, housing up to 100,000 troops. Allied air raids sank dozens of ships in Simpson Harbour between 1942 and 1945. The harbour floor is now one of the most diverse wreck dive sites in the world, with ships, aircraft, and submarines scattered across a relatively compact area in warm, clear water. The Japanese destroyer Suzunami, sunk in November 1943, lies in 25 metres of water and is completely encrusted with coral after 80 years.