La source

La source — “The Spring” — is a reef dive site in the Tahiti lagoon, French Polynesia, named for a freshwater spring that discharges from the seafloor and creates a distinctive halocline visible to divers.

Overview

The defining feature of this site is an underwater freshwater spring emerging from the sandy reef floor at around 15–18 metres depth. Where the cold, lighter fresh water meets the warmer salt water, a shimmering halocline layer creates an optical distortion effect — a lens-like shimmer that photographers seek out as a natural special effect. The surrounding reef is in good condition with a mix of tabulate and massive corals providing habitat for a diverse fish community. Visibility is typically 20–30 metres in the saltwater layers, and the freshwater plume itself may be cooler by several degrees.

What to Expect

The halocline above the spring is a highlight for underwater photographers and videographers — wide-angle shots of divers framed in the shimmering fresh/salt interface are a distinctive composition found at few sites in French Polynesia. Beyond the spring itself, the reef hosts lionfish, moray eels, and clusters of glassfish. Turtles graze the nearby coral heads, and parrotfish crunch coral throughout the dive. The mix of fresh and salt water near the spring also creates a unique micro-habitat where otherwise unusual species combinations can be observed.

Conditions

• Best season: April–November
• Visibility: 20–30 m (variable near the halocline)
• Current: Mild
• Water temperature: 27–28°C (spring area cooler)
• Entry: Boat dive

Tips

Allow time to observe the halocline effect carefully — the spring output varies with tide and season, so the visual effect ranges from a faint shimmer to a dramatic distortion. Position yourself above the spring looking up into the halocline for the most striking photographic results.

Sources: Dive and Sea Tahiti – Dive Sites, DiveOtion – Scuba Diving in Tahiti, Dive Discovery – Tahiti Diving. Last updated 2026-05-30.