A subterranean spa built into an 800-year-old lava flow forms part of a significant expansion at Iceland’s famous Blue Lagoon

Attracting up to 1 million visitors last year, Blue Lagoon geothermal springs is one of Iceland’s most popular tourist attractions.

Kim Kardashian and Beyoncé have taken to its waters, while Microsoft founder Bill Gates reportedly booked the entire site for a twilight swim.

With such growing demand, the opening of its first luxury offering, the Retreat, has been highly anticipated. The all-suite hotel, restaurant and spa – which have been in development for four years – launched in April and represent a significant expansion for the attraction.

“We’re proud to finally be able to share the Retreat at Blue Lagoon Iceland with the world,” says founder and CEO Grímur Saemundsen, who’s received awards for his progressive approach in tourism. It’s been his long-term vision for Blue Lagoon to become an epicentre for health and wellbeing. “Our team and partners have worked extremely hard to bring this luxury experience to life and we are beyond excited to welcome guests to our new property,” he adds.

Subterranean spa
The underground Retreat Spa built into an 800-year-old lava flow is a core part of the extension. Open to overnight guests and day visitors, the 4,000sq m (43,056sq ft) spa has steamrooms and saunas warmed by the heat of volcanic rocks, a cold well, a tranquil water wall and treatment rooms for massages, facials and beauty services.

Therapies use Blue Lagoon’s own skincare which is rich in minerals, while in-water watsu massages starting at ISK10,200 (US$104, €84, £73) for 30 minutes are also available. Therapist uniforms are supplied by Fashionizer Spa.

As part of a free signature ritual, guests explore a series of interconnected chambers and cover themselves in healing algae, silica mud and minerals. Or, for a more private affair, the Lava Cove is a self-contained spa suite with it’s own lagoon, wood-burning fireplace and butler.

In addition, spa visitors can access the Retreat Lagoon, a new Blue Lagoon experience, where the mineral-rich water flows around the hotel and spa through a terraced concourse of lava.

In the lounge, guests relax in suspended nest chairs while taking in views of the lagoon with floor-to-ceiling windows.

The same views are also enjoyed by those taking a break from the spa journey in the casual spa restaurant. Here, guests wrap up in bath robes to snack on light fare including Icelandic sushi and refresh themselves with cold-pressed kale juice and shots of algae.

All-suite hotel
The Retreat hotel itself boasts 62 suites designed by Milan-based Design Group Italia and Reykjavik’s Basalt Architects with a minimalist aesthetic to emphasise the dramatic terrain outside. Prices of suites start at ISK143,750 (US$1,460, €1,180 £1,029) and some rooms on the lower floor provide direct access to the lagoon.

The hotel prides itself on offering ‘intimate hospitality’. Each guest is welcomed by an individual host who will serve as their guide throughout their stay – providing insight to local culture or informing them of the imminent arrival of the Northern Lights, for example. Activities such as guided hikes taking in the striking volcanic landscape and complimentary morning yoga sessions are also on offer.

Meanwhile, the upscale Moss Restaurant in the hotel highlights seasonal and regional ingredients, including reindeer sourced by a hunter.

Four-year endeavour
It’s taken Blue Lagoon four years to complete this sizeable project, the purpose of which is to enhance the overall guest experience rather than to increase visitor numbers.

Sigridur Sigthorsdottir of Basalt Architects led the development working with EFLA, an Icelandic engineering and consulting firm. Sigthorsdottir has been the architect at the Blue Lagoon for more than 20 years and her work in harmonising the man-made and natural environment has received critical acclaim.

Blue Lagoon was founded in 1992 with the purpose of unlocking the benefits of geothermal seawater. Originally based on a single entity – a lagoon holding 6 million litres of water – the company now operates the 35-room Silica Hotel, a restaurant, an R&D centre and has its own skincare range.

The first phase of expansion in 2016, saw the main lagoon enlarged by half. And now the launch of the spa, another hotel and restaurant complete the offering.