Going for a spa in Iceland can feel wonderfully alien. Against a backdrop of barren moonscapes and denuded hills, the waters are so preternaturally blue, so exaggerated and preposterously warm, that a simple dip can feel borderline indecent. Venture from the capital Reykjavik as far as Reyðarfjörður in the extreme east and you’ll also find that the country hides hundreds of out-of-this-world geothermal pools and naturally-heated hot tubs.

But it first pays to know the rules. Because in Iceland, the right spa etiquette is taken deadly seriously. Here are five dos and don’ts to bear in mind.

Don’t forget to wash yourself

It may sound obvious, but unlike the rest of Europe, where most bathers make-do with a quick shower-room rinse, Icelanders have a set, strict routine when going for a dip that must be followed to the letter.

First, read the rules. They’re pinned to every changing room wall and notice-board, as well as being published in English, French, German and Danish, so you really have no excuse not to follow them.

Second, get washing. Scrub your head, armpits, feet and groin with soap beforehand, and – most importantly – do it in your birthday suit, not bathing suit. A quick rinse just won’t do, especially because most geothermal pools use freshwater and far lower levels of chlorine, even at the Blue Lagoon at Reykjanes.

And having just read the rules, you have no excuse not to get naked. You have been warned.

Iceland, Kjolur, hot pool at Hveravellir

Do get chatting to the locals

Approaching a complete stranger in a bikini may at first seem like a coquettish, brazen thing to do, but it’s OK in Iceland.

In Reykjavík, hot tubs and pools are more like social clubs where people catch up on news and discuss politics: and they’ve done so since the twelfth century when poet, scholar and politician Snorri Sturluson built the first stone hot tub outside Reykholt.

To get the best of the conversations, go to a local’s pool such as Vesturbæjarlaug, a short walk from Reykjavík city centre, or Nauthólsvík, a geothermal saltwater pool by a golden beach.

Around seven o’clock on a weekday morning, the conversation bubbles as much as the thermal waters. There is no social hierarchy, and everyone is treated like an equal.

For something more romantic, take a date to Sundhöll, built in the 1930s, it’s open late and is one of the oldest baths in the capital.

Iceland, Reykjavik, Laugardalur swimming pool

Don’t talk too loudly (or on your phone)

Icelanders don’t like tourists who make too much noise: period. Their dose of social media may well be a get-together in the spa, but they talk quietly, which can sound as soft as whale song.

The reason? Many spas and indoor pools were built in the 1960s and loud noises echo down the corridors of the indoor pools and steam rooms.

“Our bathhouses tend to venerate tradition above anything else,” says spa aficionado Birgir Þorsteinn Jóakimsson, who visits Reykjavik’s Vesturbæjarlaug every day. “Talking loudly is a nasty habit, especially at an Icelandic spa – so you won’t be popular with the locals. It’s not a circus.”

It also pays to be alert, as hawkish pool attendants may ambush you, showing you the door. They’ve been known to throw tourists out for less.

Iceland, pool outside the Blue Lagoon complex, near Grindavik

Don’t jump straight in

Those milky-blue waters are ridiculously tempting, but also feverishly hot. Draw the cool air into your lungs and take your time by testing the water temperature first to check your skin’s sensitivity to the geothermal heat.

In Reykjavík at Laugardalur Park, also known as the Valley of the Pools, the water used to hover at a white-hot 45 degrees Celcius, punishing unsuspecting dive-bombers. Such waters have since been cooled due to health and safety regulations, but with most still nudging upwards of 37 degrees, it’s an odd juxtaposition between bathing in hell, while feeling like you’re in heaven.

To maximise enjoyment, remember to swim in an anticlockwise direction. No one can really explain why, but Icelanders swim in circles from right to left, and so should you.

Summer in Germany

Do take a local’s advice

The most sacred pools are only known by the locals – and with good reason. Places like the old pool at Gamla Laugin at Fludir on the Golden Circle – supposedly the oldest in Iceland – or Seljavallalaug, a snooker-chalk blue outdoor pool secreted up a valley near Skogar, are so sybaritic you wouldn’t want to share them with anyone else either.

“Everyone has their favourite they want to keep,” says Guðrún Bjarnadottir, a spa professional working at the Blue Lagoon. “If you talk to locals – and they like you – you may get lucky. My personal favourite is somewhere in the hills north of Hveragerdi. It’s in a mystical place known as the Smoky Valley, but the exact location and directions – well – that would be telling.”

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