The Mahi (Wreck) is a west Oahu wreck dive on a former Navy minesweeper that now serves as an artificial reef off Waianae. Divers stay outside the structure and work the deck, rails, and surrounding sandline for a deliberate wreck tour rather than a penetration dive. It is a boat-only site with more planning overhead than a harbor reef, so calmer seas and a controlled descent matter. The wreck draws steady fish life and is a good fit for experienced divers who want a classic west-side charter day.