Lake Hillier

You can only reach it by small aircraft or boat. From the air, the lake appears to be filled with strawberry milkshake — a vivid, saturated pink pressed hard against the indifferent blue of the Southern Ocean, divided by a paper-thin strip of white sand beach and a dense green ridge of eucalyptus and paperbark forest. The contrast is so unlikely that first-time aerial viewers consistently report a moment of disbelief before their eyes accept what they are seeing. Photographs of Lake Hillier look retouched. They are not.

Lake Hillier occupies the largest island of the Recherche Archipelago — Middle Island — approximately 2 kilometers long, separated from the south coast of Western Australia by about 4 kilometers of open ocean. The lake itself is roughly 600 meters long and 250 meters wide. Its water remains pink at all times: in full daylight, in dusk light, and — uniquely among the world's pink lakes — when a sample is removed and held in a glass. Most pink lakes lose their color when taken away from their ambient conditions. Lake Hillier stays pink indefinitely.

The color has two biological sources. The primary contributor is Dunaliella salina, a halophilic alga that produces carotenoid pigments — specifically beta-carotene — as a cellular response to extreme salinity stress. In the dense salt concentration of Lake Hillier, the algae produce these orange-red pigments in quantities sufficient to color the surrounding water. The secondary contributor is halophilic bacteria in the salt crust along the lake's margins, which produce similar pigments through related metabolic pathways. Together, the two populations maintain the lake's color across all seasons and weather conditions.

Matthew Flinders — the British navigator who became the first person to circumnavigate and map the Australian continent — anchored off Middle Island in 1802 and recorded the lake in his journal with undisguised amazement. He described it as a salt lake remarkable for its rose color. His description, written in 1802, remains accurate today. The lake's color has been documented continuously for over 200 years and has not changed — evidence that the biological processes maintaining it are stable and self-sustaining across any timescale relevant to human observation.

The lake is protected as part of the Recherche Archipelago Nature Reserve; independent access is not permitted. Supervised day tours by seaplane from Esperance — the nearest mainland town, approximately 700 kilometers east of Perth — are available during warmer months. The seaplane approaches low over the lake on its landing run, providing the aerial view that has made Lake Hillier one of the most widely reproduced aerial photographs in Australia. The landing is on the ocean side of the island; the lake is reached on foot through coastal scrub. The shore-level view — standing at the water's edge, the pink surface extending to the far bank, the eucalyptus canopy behind, the Southern Ocean audible beyond the sand bar — is a different experience from the aerial one. Less comprehensive but more immediate. The color at that distance is something you feel as much as see.