Spas with solo travelers

New York City, New York

A Flatiron bathhouse with six thermal pools, a banya, dry and infrared saunas, a steam room and a salt pool, day pass from $39.

Oslo

Waterfront sauna spot on Aker Brygge with shared and private saunas, sea bathing, and sauna boat trips on the fjord.

Gold Coast, Queensland

A 90-minute hydrotherapy circuit in Southport with a Finnish rock sauna, 5° ice baths and hot/cold magnesium pools, day pass $49.

Noboribetsu, Hokkaido

A plain neighborhood bathhouse in Noboribetsu, Hokkaido, offering 100% source-fed hot spring water in two mineral varieties, about 10 minutes from the station.

Zanzibar

A moderate-priced day spa and hammam in Stone Town offering over 50 treatments, including Ayurvedic therapies and a sauna.

Gothenburg, Västra Götaland County

A hammam in Gothenburg's Olivedal district offering traditional oriental-style treatments, open daily from 9am to 10pm.