Blue Cave (Tanna) - Tanna

25m Max

15-35m Vis

shore

Site Overview

Blue Cave (Tanna) is one of the signature dive sites of Tanna – Blue Cave, Outer Reefs & Volcano in Vanuatu. A breathtaking limestone cavern accessed by a short underwater swim-through at 3 m depth, opening into a large chamber with intense blue-light refraction, stalactites and glassfish, with snorkelling and scuba around the entrance and macro life and rays. The site reaches a maximum depth of about 25 m, with an average depth near 15 m, and its cavern, swim-through topography is draped in limestone, coral. Marine life is the headline attraction, with Glassfish, Flashlight fish, Reef lobster, Soft coral gardens, Moray eel, Lionfish, Spotted eagle ray regularly recorded here, drawn in by the mild currents and the rich coral-reef productivity of the region. Visibility typically ranges from 15 to 35 m, while water temperatures hold a consistent 24 to 29 C year-round, comfortable in a 3 to 5 mm wetsuit. Conditions suit intermediate divers, and with the right guide the site delivers both the drama of its cavern, swim-through and intimate encounters with the smaller residents. Local operators run regular trips from Lenakel, Tanna, and the protected, low-tourism setting keeps coral cover dense and fish life abundant, making Blue Cave (Tanna) a genuine standout on any Vanuatu itinerary. Divers who time their visit to the dry season will find the most predictable conditions, though the site rewards repeat visits across the year.

Dive Briefing

"The dive at Blue Cave (Tanna) 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 Lenakel, Tanna. Descending toward the cavern, swim-through profile, divers are immediately surrounded by Glassfish, Flashlight fish, Reef lobster, Soft coral gardens, Moray eel, with the reef and structure revealing more detail the closer you look. The maximum depth reaches about 25 m while the average sits near 15 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 surface marker 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 surface marker, and the boat follows the bubbles to collect divers at the exit point for a relaxed return to base. Blue Cave (Tanna) is best dived from April to November, Vanuatu's dry season, when settled seas and the clearest water make for the most reliable conditions. The mild current is at its calmest around slack tide, so most operators plan the descent to coincide with the turn of the tide. Water holds 24 to 29 C, and a 3 to 5 mm wetsuit is ample. Plan a slow profile to enjoy the 3 to 25 m range and to protect the fragile reef with good buoyancy. A torch helps reveal the smaller residents, and a surface marker buoy is recommended for the safety stop so the boat can track divers in the often gentle swell."