Saturday night out in a very special way. Spa, prosecco and ice blue water, set in the heart of a stunning lava landscape. The Blue Lagoon geothermal spa is one of the most visited attractions in Iceland. And I get why. The water temperature is generally between 37-40°C (98-104°F). The lagoon contains 9 million litres of water. The water is self-cleansing – it renews itself every 40 hours. Blue Lagoon is mostly ca. 0.8-1.2 metres deep. Its deepest point is 1.6 meters.