Olympia Maru
Depth is the range from the top of the site to its usual maximum; "recommended cert" is the mainstream-agency level operators usually ask for, not a legal rule. Currents and visibility change daily — treat everything here as planning ranges.
The Olympia Maru, a freighter in the 120 m class from the same September 1944 catastrophe, is the fleet's crowd-pleaser: shallow enough for relaxed bottom times, big enough to feel like an expedition, and colonized to the waterline of its former life. Batfish escort divers along the hull in loose formation, glassfish pour out of companionways in silver smoke, and scorpionfish upholster the winches. Holds and engine spaces offer straightforward guided penetration lines with visible exits for those with training. As an introduction to what Coron does, most guides start people here or on the Okikawa, and few argue.
The moment you come for: Batfish escorts and glassfish clouds, forgiving depths, an ideal first Coron wreck
Topography: Hull on its side on sand around 25-30 m
Know before you splash
Hazards: Silt and sharp edges; easy to overstay on the deeper sand line.
Conservation: Same protections as the rest of the 1944 fleet; the growth on the hull is decades old and irreplaceable.
Nitrox: Worth it here — profiles sit in the range where enriched air meaningfully extends no-stop time (with the training to use it).
Who you'll meet
Broadclub Cuttlefish
Giant Moray Eel
Lionfish
Nudibranchs
Pinnate Batfish
For photographers
Wide angle: ★★★★☆ · Macro: ★★★☆☆ — editors' 1–5 rating of what this site gives each style of shooting