Kastrup Sea Bath: Copenhagen's Free Harbour Bath Guide

What Kastrup Sea Bath is

The bath is a sculptural wooden structure designed to be visible from land, sea and air, built from red ironwood chosen for its resistance to salt water. It describes three quarters of a circle on plan, and the deck rises continuously as it curves, so the walk out is also a gentle climb. The design shelters bathers from the wind while opening toward the shore to catch the evening sun.

You reach the water via a 100-metre causeway, with the platform itself supported on 150 piles above the Baltic. Around 900 square metres of deck gives room to lay a towel, change position as the sun moves and find a corner out of the breeze. Floor spots light the structure after dark, which makes an evening swim a different experience from a midday one.

Where it sits

The bath belongs to Kastrup on the island of Amager, on Copenhagen's eastern edge and close to Copenhagen Airport. That location makes it a practical first or last swim of a trip: the city centre is a short metro ride away, and planes pass low overhead as you dry off.

From the platform you look back across the Øresund toward Copenhagen rather than out at open sea, so the swim comes with a skyline and shipping traffic. The setting is urban rather than wild, and the wind off the water is the thing most bathers notice first. Wet boards, salt spray and a stiff breeze are part of the experience on a grey day.

How a swim works

There is no booking and no entry fee. The bath is open around the year and free to use, and you swim at your own responsibility. In summer, service staff are on site daily from 15 May to 31 August, between 14.00 and 18.00, and can be reached by phone in that window. Outside those afternoon hours, you are on your own.

A visit is simple: walk the causeway, change, swim, dry off, walk back. There is no reception desk, no timed session and no queue system, so the rhythm of the day is set by the weather and by how long you can stand the cold. Check the yellow and red flag before you commit. A yellow flag means bathing is discouraged, and a red flag means you must stay out.

Facilities and what to expect

The bath has changing rooms and toilets, including accessible changing facilities. The deck is generous enough for groups to spread out, and the curved form creates pockets of shelter from the wind. There is a five-metre diving point at the high end of the platform for those who want a jump rather than a ladder entry.

What you will not find is a sauna, heated water or a café. The sea is the whole point, and the water is cold even in high summer. Bring your own towel, swimwear and something windproof, plus footwear for the causeway if the boards are wet or gritty.

Cold water and the sauna habit

A dip at Kastrup fits the Nordic pattern of cold water followed by heat, except that the heat has to happen somewhere else. Copenhagen has plenty of options, from harbour baths to city saunas, and our guide to the saunas in Copenhagen sets out which ones take walk-ins, which run mixed sessions and which sit closest to the water.

If you want the genuine article, look for a proper Finnish sauna and treat the sea dip as the cooling round. The Finnish sauna is the reference point for how this works: a hot room, a short stay, then cold water, repeated a few times. A round of five to fifteen minutes in the heat, followed by a plunge, is the usual rhythm. Our guide to the Finnish sauna explains the pattern, and Allas Sea Pool in Helsinki shows how a harbour-side sauna and a cold pool are meant to sit together.

Season, crowds and water quality

Summer afternoons are the busiest time, when the service staff are present and the deck fills with families and swimmers. Outside that window, in spring, autumn and winter, the bath is quiet and the swim is brisk rather than social. The water quality at Kastrup is regularly tested and sits in the best category, which matters more here than at a chlorinated pool.

Do not go in if there are algae nearby, if there has been heavy rain for a long stretch, or if you cannot see your feet standing knee-deep. The flags carry the same message in a simpler form: yellow for discouraged, red for forbidden. Cold-water swimming calls for a clear head, so skip alcohol beforehand, supervise children and get out if you start to feel unwell. Anyone with a heart condition or who is pregnant should ask a doctor before making a habit of it.

Getting there

Kastrup is served by metro and bus, with the airport and the town centre both within reach of the bath. The final stretch is the 100-metre causeway, which is exposed to the wind and worth dressing for. Allow extra time on a cold day: the walk back in wet swimwear is the part people underestimate.

Nearby alternatives

If you want a harbour bath in the city itself, Islands Brygge harbour bath is the best-known, with a larger swimming setup and a busier summer scene. La Banchina, Copenhagen, on Refshaleøen, pairs a swim in the harbour with a sauna and something to eat, while CopenHot and the Sauna House Nordhavn offer wood-fired heat with a sea view.

For something less urban, Green Island Copenhagen and Winter Island offer a different pace, and both work well as a cold-water round in the Nordic style. Our guide to saunagus explains the ritual that many Copenhagen saunas run, with aromatics and a towel to wave the heat around. If you end up in Aarhus, the Frederikshavn Svømmehal is worth knowing for its volcanic steam room.

Plan Your Visit

Kastrup Sea Bath is the Copenhagen swim to choose when you want architecture, a cold sea and no ticket: free, open year-round, and best paired with a sauna elsewhere in the city. Go in the late afternoon for the low sun on the ironwood, or on a cold, clear morning when the deck is empty. Check the flags on the Tårnby municipality page before you travel.