Seiun Maru - Subic Bay

The Seiun Maru is one of those Subic Bay wrecks that truly tells a story. We love how the hull opens up in places, letting shafts of light cut through the gloom, illuminating the big cargo holds. Dropping down, you’ll often feel a slight chill as you approach the metal, a stark contrast to the tropical surface. Our favourite moment is always finning past the stern, where you can still make out the large propeller and rudder, often draped in soft corals and sponges. It's a fantastic dive for advanced open water divers who appreciate wreck penetration without needing a full technical setup. The resident batfish schools are massive here, swirling around the deeper sections, and we’ve spotted giant frogfish clinging to the superstructure, masters of camouflage. We’d suggest going early in the morning; the visibility tends to be better before the boat traffic picks up, and the light penetration into the holds is just magic. Keep an eye out for nudibranchs on the deck plating, too; they're surprisingly common.

Location: Subic Bay, Philippines, Southeast Asia
Coordinates: 14.809750, 120.281980
Type: wreck

Marine Protected Area: Sabang Marine Protected Area

Best Time to Dive in Subic Bay

The warmest water temperatures in Subic Bay occur in May, averaging 31.4°C. The coolest conditions are in February at 28.2°C.

Monthly Water Temperatures

January: 28.4°C
February: 28.2°C
March: 29.4°C
April: 30.5°C
May: 31.4°C
June: 31.3°C
July: 30.8°C
August: 29.8°C
September: 30.0°C
October: 30.4°C
November: 30.4°C
December: 29.4°C

Nearest Dive Centres to Seiun Maru

Arizona Dive Shop - PADI
Blueworld Dive Center - ["PADI"]
Camayan Divers - ["PADI"]
Dive Buddies Philippines - ["PADI"]
Divers Point
Ocean Deep - Diver Training Center (PADI)

Marine Life in Subic Bay

Home to 63 recorded species including 49 reef fish, 6 seagrass & algae, 5 hard corals, 2 sharks & rays, 1 sea snails & nudibranchs.

Notable Species

Flagfin Mojarra (Gerres filamentosus) - Reef Fish
Species code: Ea (Enhalus acoroides) - Seagrass & Algae
Crescent Grunter (Terapon jarbua) - Reef Fish
Bar Eyed Goby (Glossogobius giuris) - Reef Fish
Green Rrough-backed Puffer (Lagocephalus lunaris) - Reef Fish
Silver Sillago (Sillago sihama) - Reef Fish
Common Ponyfish (Leiognathus equula) - Reef Fish
Toothed Ponyfish (Gazza minuta) - Reef Fish
Blacktip Ponyfish (Eubleekeria splendens) - Reef Fish
Honeycomb coral (Favites abdita) - Hard Corals
thalassia (Thalassia hemprichii) - Seagrass & Algae
halodule (Halodule uninervis) - Seagrass & Algae
Six-banded Rock Cod (Epinephelus sexfasciatus) - Reef Fish
Silverfish (Trichiurus lepturus) - Reef Fish
Silver Javelin (Pomadasys argenteus) - Reef Fish
Staghorn coral (Acropora millepora) - Hard Corals
Canif (Aeoliscus strigatus) - Reef Fish
Butterfish (Scatophagus argus) - Reef Fish
Puntang Goby (Exyrias puntang) - Reef Fish
Giant Herring (Elops hawaiensis) - Reef Fish

Recommended Packing List for Seiun Maru

Based on average water temperature of 30.0°C, currents 3 cm/s.

Shorty or Rashguard - warm 30°C water needs minimal exposure protection
Mask - essential for every dive
Fins
BCD - buoyancy compensator
Regulator - your most safety-critical piece of gear
Dive Computer - tracks depth, time, and NDL
Surface Marker Buoy (SMB) - essential for boat pickups
Dive Torch - useful for crevices and colour at depth
Underwater Camera - capture your diving memories