I-1 Japanese Submarine (Tambea) - Guadalcanal – Honiara & Iron Bottom Sound

15m Max

12-25m Vis

boat

Site Overview

I-1 Japanese Submarine (Tambea) is one of the signature dive sites of Guadalcanal – Honiara & Iron Bottom Sound in the Solomon Islands. The 98 m Japanese Type I-1 submarine was sunk in 1943 and now lies torn open by depth charges in shallow water, its torpedo tubes still visible and the hull draped in coral with moray eels and lionfish. The site reaches a maximum depth of about 15 m, with an average depth near 10 m, and its wreck topography is draped in metal and coral. Marine life is the headline attraction, with lionfish, moray eel, coral-encrusted hull, glassfish, nudibranch, batfish regularly recorded here, drawn in by the mild currents and the rich Coral Triangle productivity of the region. Visibility typically ranges from 12 to 25 m, while water temperatures hold a consistent 27 to 30°C year-round, comfortable in a 3 to 5 mm wetsuit. Conditions suit beginner divers, and with the right guide the site delivers both the drama of its wreck and intimate encounters with the smaller residents. Local operators run regular trips from Honiara, and the protected, low-tourism setting keeps coral cover dense and fish life abundant, making I-1 Japanese Submarine (Tambea) a genuine standout on any Solomon Islands itinerary. Divers who time their visit to the calm season will find the most predictable conditions, though the site rewards repeat visits across the year.

Dive Briefing

"The dive at I-1 Japanese Submarine (Tambea) begins with a thorough operator briefing covering the site layout, expected marine life and emergency procedures, followed by a controlled entry and a short transfer from Honiara. Descending toward the wreck profile, divers are immediately surrounded by lionfish, moray eel, coral-encrusted hull, glassfish, nudibranch, batfish, with the reef and structure revealing more detail the closer you look. The maximum depth reaches about 15 m while the average sits near 10 m, so a dive computer and disciplined gas planning keep the profile safe and comfortable. Currents are described as mild, and the guide chooses the entry time to make the most of slack or mild flow, using a reef hook or DSMB when needed. Neutral buoyancy protects the fragile coral and the group stays close to manage depth and any surge. The safety stop is completed in open water on a DSMB, and the boat follows the bubbles to collect divers at the exit point for a relaxed return to base. The I-1 submarine is best dived as a shallow boat dive on a calm day, when the torn-open pressure hull and visible torpedo tubes are easiest to appreciate. The 5 to 15 m depth means long bottom times and no decompression, ideal for a relaxed profile. Water stays 27 to 30°C, and a 3 mm wetsuit is plenty. A morning dive gives the clearest water."