Coron · Philippines · Wreck
Olympia Maru
Upright and intact, deck at 18-24 m, holds open
Area photo: Ray in Manila · CC BY 2.0
A timber hauler converted into a mobile aircraft repair facility and supply depot, sunk by US air attack on 24 September 1944 and now upright and intact off Sangat Island in Coron Bay. The main deck sits at 18 to 24 m with the bottom at 30 m, and the cargo holds are open, which is why she is dived as an advanced wreck rather than a swim over the outside.
Where it is and how deep
11.9707° N, 120.0613° EPublished position for this site.
The dive
She remains upright and intact, which makes her one of the more readable wrecks in the bay. Most of the diving happens between 10 and 25 m, with the main deck at 18 to 24 m and the deepest point of the ship at 30 m, so a normal dive works along the deck and superstructure and only drops to the sand where there is a reason to. Visibility on the wreck usually runs 10 to 20 m.
The cargo holds are accessible and are the reason the site carries an advanced rating rather than an easy one. Penetration here is a genuine overhead environment: light falls away quickly once you are inside the hull, and a hold that reads as open on the way in can turn opaque behind a badly placed fin. Divers without wreck training get plenty out of staying on the outside of the ship.
The growth over the upper structure carries the marine life. Hard and soft coral and sponges cover the plating, batfish, lionfish, scorpionfish and pufferfish work over it, groupers hold in the shaded spaces, nudibranchs sit in the growth and barracuda and turtles pass over the deck. The shallow end of the wreck, around 10 m, is where the safety stop lands, which usually means finishing the dive over the most heavily encrusted part of the ship.
The wreck
- Vessel
- Olympia Maru
- Type
- Timber hauler converted to aircraft repair and supply ship
- Sunk
- 1944
- Cause
- Sunk by US air attack
- Lies
- Upright and intact, main deck at 18-24 m, bottom at 30 m
The Olympia Maru began as a timber hauler and was converted into a mobile aircraft repair facility and supply depot for the Japanese Army. She witnessed and survived the US Navy attacks in Manila Bay, then withdrew to Coron Bay for safety - the same reasoning that gathered the fleet now on the bottom there. The air raid on Coron Bay set her on fire, and she was sunk on 24 September 1944, the day US Task Force 38 aircraft worked through the anchorage.
Marine life and season
- Groupers
- Barracuda
- Nudibranchs
- Sea turtles
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Prime | Prime | Prime | Prime | Fair | Fair | Fair | Fair | Fair | Fair | Fair | Prime |
Season follows Coron: Dry December to April brings glassy seas and the best visibility; in the wet months bad weather sometimes stops diving.
Know before you go
- The holds are an overhead environment inside a large hull; penetration needs wreck training, a torch and a plan for the way out.
- The bottom is at 30 m, so dropping off the deck to the sand shortens the dive quickly - agree the maximum depth before you go in.
- Current on the wreck is rated medium, so make the descent on the line and check the drift before leaving it.
Questions divers ask
Do you need wreck training for the Olympia Maru?+
Not for the outside. The deck sits at 18 to 24 m and the usual profile runs between 10 and 25 m, which suits an advanced diver. The cargo holds are accessible but are an overhead environment, and that part of the dive needs wreck training and a torch.
Sources
- Olympia Maru dive site — Divezone
- Olympia Maru — Scubago
- Olympia Maru — PADI
- Coron Bay — Wikipedia
More dive sites in Coron
Wreck
A 35-ton seaplane crane on a warship lying on her side at 35 m
Fresh water over salt, and 38 degrees below the thermocline
Reef
A channel drift at 1 to 3 knots between two wrecks
Cave & cavern
A fallen tree lit by daylight inside a cavern under Coron Island
Coral garden
Very large sea fans among soft-coral gardens
A 35 m gunboat in 3 to 19 m, open to any certification
Wreck
A 145 m provisions ship with its deck areas at 28 to 35 m
Wreck
A bulldozer and cement bags still in the cargo holds
Similar dives elsewhere
Wreck
Cement Wreck
Labuan & Brunei Wrecks · Malaysia
MV Tung Hwang: a 92 m freighter standing upright off Labuan from 8 m to 32 m
A fish-filled wreck at 30 m below a patchy coral slope
A two-seat aircraft sunk on sand at 20 m, with a wall beyond
A 125 m cargo ship on a sand slope 30 m off the beach