2 answers. The lagoon is safe to swim and snorkel in. There are no sharks, croccodiles or box jellyfish. There is nothing that will harm you.
The land is natural, as is the lava that shapes the pool, but the hot water is actually the result of runoff from the geothermal power plant next door. The runoff is filtered straight into the Blue Lagoon, which is what heats the water. That doesn't mean it's dangerous or toxic — far from it!
And we do mean “clean†quite literally – the Blue Lagoon strictly enforces its hygiene rules. Guests are required to shower – with soap, not just a rinse – before entering the water out of respect for other bathers and the site itself.
These include the silica mud mask, sauna and steam rooms, a human-made waterfall, a cave to relax inside, an in-water bar, the option to book an in-water massage, and an indoor relaxation area with a view over the lagoon itself. You can get the silica mud mask from the mud bars inside the lagoon.
Open-pit quarries exist in many rural parts of the world, and they often entice swimmers who don't have easy access to the sea. Yet quarries are sometimes toxic and even deadly. Local government officials posted signs, warning of the water's toxicity, but that didn't deter swimmers.
The water's milky blue shade is due to its high silica content. The silica forms soft white mud on the bottom of the lake which bathers rub on themselves. The water is also rich in salts and algae. The water temperature in the bathing and swimming area of the lagoon averages 37–39 °C (99–102 °F).
The Blue Lagoon is designed for relaxed bathing. You don't need to know how to swim to visit the Blue Lagoon. There are many areas where the water is shallow enough that it doesn't pose a danger to non-swimmers. At the edges of the lagoon, the depth less than 0.8m/2.6ft—perfect for lounging and relaxing.
Pools and hot tubs often serve as a hub of social activity in Iceland, and while the Blue Lagoon may not provide that every time, it's a good place to get started. It's worth the trip for the opportunity to take in the natural beauty of Iceland: in its waters, its views and way of life.
There are generally significant suspended fine solids (rock flour like loess) in quarry water. This would appear milky white in a small amount of water, but in a deep quarry, like those in many images, the effect is to amplify the naturally blue appearance of the water in sunlight.
The best time to visit the Blue Lagoon is either in the morning or evening to avoid crowds. If you go in the evening, you may see the northern lights or midnight sun during your excursion, depending on whether you visit in the winter or summer.
How deep is the Blue Lagoon? The deepest area in the Blue Lagoon is 1.4m/4.7ft. and the shallowest area is less than 0.8m/2.6ft.
