Îlot Signal sits 1.8 kilometres northwest of Anse Vata, a 2.3-hectare limestone outcrop that marks the boundary between Nouméa's sheltered harbour and the open Pacific reef system. French colonial charts from 1874 named the island for the semaphore station erected on its southern ridge, which relayed shipping intelligence between Port Moselle and the outer barrier reef until radio transmission rendered flagpole signals obsolete in 1912. The station's stone foundations remain visible beneath frangipani canopy, though the island's value shifted decisively in 1981 when marine biologists documented a resident green turtle population—*Chelonia mydas*—using the surrounding seagrass beds as a permanent feeding territory rather than a seasonal waypoint. That discovery transformed Îlot Signal from a recreational anchorage into New Caledonia's most accessible marine wildlife observation site. The island's western shore drops into a shallow lagoon basin where water depth rarely exceeds four metres, creating ideal conditions for snorkelers to observe turtles grazing on algae and resting on coral ledges without the buoyancy challenges of deeper reef environments. Provincial biodiversity surveys between 2019 and 2023 recorded an average of eleven individual turtles within the western 800-metre zone during daylight hours, with morning density peaking between 08:00 and 11:00 when tidal currents carry nutrient-rich water across the seagrass flats. The lagoon floor here is a mosaic of *Porites* coral bommies, white sand channels, and turtle grass meadows—*Thalassia hemprichii*—that together support a micro-ecosystem dense enough to hold a visitor's attention for an hour without relocating. Noumea boat operators began running signal island turtle tour from noumea excursions in the mid-1990s, initially as adjuncts to Amédée Lighthouse itineraries, but by 2003 the turtle encounter itself had become the primary draw. Modern tours depart from Port Moselle or Anse Vata marinas aboard aluminium catamarans and rigid inflatables, crossing the lagoon in eighteen to twenty-three minutes depending on departure point and sea state. The island itself remains uninhabited and undeveloped aside from a composting toilet installed by the Southern Province in 2017; no commercial infrastructure exists onshore, reinforcing the site's role as a pure marine observation platform rather than a beach resort. That restraint has preserved the turtle population's behaviour patterns—individual animals here show minimal flight response to human presence, allowing mask-and-snorkel observation at distances measured in metres rather than tens of metres, a proximity threshold rarely achieved at heavily trafficked reef sites elsewhere in the South Pacific.