Iceland’s Blue Lagoon, Privately: The Retreat Spa After Hours

Soak in the Retreat Spa's secluded lagoon after the day's visitors have gone, with a silica ritual and in-water treatments paced to you.

The Lagoon When the Crowds Have Gone

The Blue Lagoon lies in a lava field on the Reykjanes Peninsula, 25 minutes from Keflavík International Airport, its milky blue water steaming across black basalt. It covers around 10,000 square meters, stays at 99 to 104°F all year and is one of National Geographic’s 25 Wonders of the World. By day it’s busy and tightly choreographed. In the evening the numbers fall, sound fades across the lava plain and the water moves more slowly.

This experience takes place in the Retreat Spa, the lagoon’s most secluded part, carved 2,300 square meters into the same lava field, after general admission has closed. You come in by a discreet entrance cut into the rock, separate from the main lagoon, to a private changing suite for two and a wristband that opens every door. The water is the same; what changes is how many people share it and how slowly the evening is allowed to unfold.

A Spa Born of a Power Plant

The Blue Lagoon isn’t a natural hot spring in the traditional sense, nor was it designed as a spa. It began as runoff from the Svartsengi geothermal power plant, which started operating in 1976; water from the plant pooled in the lava field, and within a few years locals noticed it helped skin conditions, psoriasis in particular. Scientists began studying it, the Blue Lagoon company was founded in 1992, and the lagoon became both a research site and a symbol of Iceland’s renewable energy.

Its blue comes from silica, which reflects sunlight, makes the water opaque and forms the basis of the mud masks. The other active ingredients are the algae that grow in the water and the minerals rising from below, including salt, sulfur and trace elements from the volcanic rock. Bathing in Iceland has always been practical rather than ceremonial, with hot water heating homes and filling community pools, and the lagoon is a modern, researched version of that. The Retreat Spa opened in 2018, built into the lava in concrete, stone and glass that follow the land’s contours, alongside the Retreat Hotel, whose rooms and suites open directly onto the lagoon. Its restaurant, MOSS, holds a Michelin Key.

Quiet, and Paced to You

In peak hours the main lagoon holds thousands, with mud from wall dispensers and shared steam rooms: the same water, but in a public space. The Retreat Lagoon takes a fraction of that number, phones aren’t allowed and staff will take photographs if you ask. After hours, with no one arriving, the surface calms, treatment rooms run without overlap and silence holds.

Private access also means the evening follows how your body responds, not a timetable. Water temperature, the order of treatments and time spent floating or resting are adjusted to you, which matters where heat and mineral density affect everyone differently. Without distraction, you notice the silica on your skin, the water’s buoyancy and the warming and cooling cycles at the heart of Icelandic bathing. With a changing suite for two, it’s made for couples.

The Ritual and the Circuit

Three connected ritual chambers take you through the four-step Blue Lagoon Ritual: a mineral salt scrub, a silica mud mask, an algae mask and finally algae body oil, each drawn from the lagoon’s own ingredients, in about forty-five minutes. The circuit continues through a low steam cave cut into the rock beside the water, a sauna looking over the Blue Lagoon and lava field, a lava spring, a cold plunge at around 43°F and a darkened rest room.

The Retreat Lagoon itself, at 99 to 102°F, is narrower and more enclosed than the main lagoon, with lava walls rising straight from the water on two sides and the lava field beyond the windows on the others. Steam gathers on the rock, the silica-clouded water looks still at rest, and as night falls the light reflects off water and stone rather than coming from fixtures. Treatment rooms open onto the water, where silica masks are applied slowly in the lagoon itself.

Lava Cove, Massage and MOSS

For complete seclusion, Lava Cove, a 42-square-meter private suite with its own 28-square-meter warm lagoon and a fireplace, can be booked by the hour. In-water massage uses the warmth and buoyancy of the geothermal water to support the bodywork, and float therapy is also offered; both are booked separately from spa access. MOSS serves lunch and dinner over the lava field, with a tasting menu built entirely on Icelandic ingredients.

After-hours access to the Retreat Spa is tightly controlled and not publicly available. Out Of Office arranges it through established partnerships, working with Blue Lagoon management to time your visit for the best conditions and least activity, with group sizes kept small. Treatments, timing and pace are set in advance around your comfort with heat and immersion, the on-site specialists are briefed, and your LGBTQ+ travel specialist handles private transfers across the Reykjanes Peninsula and whatever comes after.