Dive Site: Tulagi - Twin Tunnels

About Tulagi - Twin Tunnels

The Twin Tunnels dive site is situated on a seamount approximately one kilometer southeast of Tulagi Island in the Solomon Islands. This site is renowned for its distinctive geological features: two ancient lava tubes that plunge vertically from a plateau, creating an exhilarating descent into an expansive horizontal cave system. The seamount rises from depths of several hundred meters, with its plateau topping out at around 16 meters before the tunnels begin their drop. The tunnels themselves are wide enough for divers to navigate comfortably, lined with an array of colorful corals and brightly hued fans as you descend. At a depth of approximately 34 meters, each tunnel opens into a large cave that then leads out onto a dramatic coral-covered wall. This topography creates a unique environment that supports diverse marine ecosystems, from resident cave dwellers to pelagic fish. Marine life is abundant, with hundreds of anemone homes on the plateau hosting at least eight different species of anemonefish. Inside the caves, you can spot nocturnal species like soldierfish, squirrelfish, and bigeyes. Along the wall and on the seamount's current-facing edge, a multitude of reef fish, including angelfish, wrasse, butterflyfish, bannerfish, blanquillos, and schools of fusiliers and midnight snapper, can be observed. The corals here are exceptionally healthy and varied, contributing to a vibrant underwater landscape. Diving the Twin Tunnels typically involves a descent into one of the vertical shafts, exploring the cave and wall section, and then ascending along the seamount's face, making sure to spend time exploring the shallower plateau. The combination of unique geology, healthy corals, and rich marine life makes this a highlight for divers visiting the Florida Islands.

Dive site facts: Tulagi - Twin Tunnels

Depth

16–36 m

Typical dive

30–40 min

Current

Mild to moderate

Visibility

30 m+

Water temperature

28–30°C

Entry

Liveaboard tender

Level

Advanced Open Water

Dive type

Wall, cave, seamount

Night dive

Possible

Region / port

Florida Islands, Tulagi

Coordinates

-9.1, 160.15

Conditions & Currents

Currents at Twin Tunnels are generally mild, especially within the protected confines of the tunnels and cave. However, a noticeable current often flows along the outer edges of the seamount, particularly on the side facing the open ocean. This current brings nutrients, attracting various feeding fish species, and is usually manageable without the need for a reef hook. Dives are typically planned to minimize swimming against the current. Visibility is usually excellent, around 30 meters, though occasional fluctuations may occur without a distinct seasonal pattern. Water temperatures are consistently warm, ranging from 28 to 30 degrees Celsius.

Marine life & sighting chances

Anemonefish

common

Soldierfish

occasional

Squirrelfish

occasional

Bigeyes

occasional

Angelfish

common

Wrasse

common

Butterflyfish

common

Bannerfish

common

Blanquillos

common

Fusiliers

common

Midnight Snapper

occasional

Anthias

common

Pygmy Seahorses

occasional

Squat Lobsters

occasional

Dive profile & how the dive runs

Your dive at Twin Tunnels begins with a descent from the liveaboard tender onto the seamount's plateau at approximately 16 meters. From there, you will enter one of the two vertical lava tubes, which are spacious enough for comfortable entry, often in a sky-diving posture. You'll descend through the tunnel, observing the colorful fan corals lining its walls, to a depth of about 34 meters. At this depth, the tunnel opens into a large horizontal cave that leads directly out onto a dramatic coral wall. After exploring the cave and the initial section of the wall, the dive typically proceeds by ascending along the wall, exploring the diverse reef life. The final phase involves a safety stop and further exploration of the shallower sections of the seamount plateau, which is rich with anemone gardens and schooling fish, before surfacing to the tender.

Underwater photography

Twin Tunnels offers diverse photographic opportunities, making both wide-angle and macro lenses highly suitable. Wide-angle is ideal for capturing the grandeur of the vertical lava tubes, the silhouette shots from within the cave, and the expansive coral wall and schools of pelagic fish on the seamount's edge. For these shots, external strobes will enhance color and detail in the deeper, darker areas. Macro lenses excel on the plateau and shallower reefs, where you'll find numerous anemonefish, pygmy seahorses, and other small critters hidden among the vibrant corals. Pay close attention to buoyancy, especially when navigating the tunnels and within the cave, to protect the fragile environment and ensure clear shots. Ethical photography dictates maintaining respectful distances from marine life and avoiding disturbing the delicate coral formations.

Combine with nearby dive sites

• Leru Cut

  A stunning natural chasm with unique light effects.

• Custom House Reef

  Known for diverse reef life and healthy corals.

• P-39 Airacobra Wreck

  A shallow plane wreck covered in corals and teeming with fish.

• Honiara - Iron Bottom Sound

  Famous for its extensive collection of WWII wrecks.

• Njari Island - Manta Point

  Offers opportunities for manta ray encounters.

• Mary Island

  Known for large schools of pelagic fish and strong currents.

Getting there & logistics

Diving Twin Tunnels is primarily conducted via liveaboard expeditions, such as the Solomons Master or Bilikiki, which typically depart from Honiara. Most itineraries explore a mix of WWII wrecks, coral gardens, walls, and unique geological formations across the Russell and Florida Islands. Trips usually range from 7 to 10 nights, offering multiple dives per day. International flights typically arrive at Honiara International Airport (HIR). Liveaboards provide tender services to dive sites, offering easy access even for those with mobility considerations. There are no specific entry fees mentioned for this particular dive site, as access is usually managed through liveaboard packages.

Safety & environment

While diving conditions at Twin Tunnels are generally benign with mild currents and warm water, all divers should hold an Advanced Open Water certification due to the depths involved and the cave environment. Maintaining excellent buoyancy control is crucial, especially within the tunnels and cave, to avoid contact with the fragile formations and prevent stirring up silt. The nearest recompression chamber is in Honiara, which is a significant distance. Therefore, comprehensive dive insurance covering emergency medical evacuation is highly recommended. Always dive within your training limits and follow your dive guide's instructions. Ensure your gear is well-maintained, and bring a dive light for exploring the darker sections of the cave.

Who it suits — and who it doesn't

FAQ

Tulagi - Twin Tunnels FAQ

Liveaboards diving Tulagi - Twin Tunnels

These liveaboards may visit Tulagi - Twin Tunnels on selected itineraries — the exact dive sites depend on departure, weather and conditions.

Solomons Master

Solomon Islands

16 guests

$401/day

Emperor Bilikiki

Solomon Islands

20 guests38 m

$567/day

Pacific Master

Solomon Islands

20 guests30 m

$268/day