Coco Beach Club is a beautiful spa (and hotel and restaurant!) in the archipelago. My favorite part is the sauna right by the sea, where you can take a refreshing dip in the ocean after warming up. The spa also has several pools, cozy relaxation areas, and another sauna to enjoy.

You can book a full day pass or just visit for the morning or evening. Book your spa visit here: https://www.ellerybeachhouse.com/en/

If you’re coming by public transport, you can plan your trip at SL.se. Take the subway to Ropsten, then switch to a bus to reach the spa.