YO-257

The YO-257 is a decommissioned U.S. Navy vessel sunk in 1989 as part of an artificial reef project off Waikiki, Oahu, Hawaii. The 175-foot-long wreck sits at 115 feet (approximately 35 m) deep, with its deck at around 80 feet (24 m). It is accessed by boat from Waikiki, where the ride out offers views of Diamond Head and Honolulu's skyline, and the site lies less than 20 minutes from the coast.

The wreck offers several penetration points of varying difficulty and is well suited to underwater photography, with visibility ranging from 60 to 80 feet (20–27 m). Corals and aquatic plants have established themselves across the structure. Given the depth, bottom time typically runs 20 to 35 minutes depending on which portion of the wreck is explored, making a specific dive plan essential before entry.

Marine life at the YO-257 includes green sea turtles, eagle rays, manta rays, whitetip, blacktip, and Galapagos reef sharks, nudibranchs, dolphins, and whales. A commercial submarine passes the wreck daily, which can provide unusual photo opportunities but requires divers to keep clear of its propulsion system.