Spas with solo travelers

San Francisco, California

Adults-only Russian bathhouse in San Francisco's India Basin with steam rooms, cold plunge, rooftop deck and a café, open daily except Tuesday.

Saratoga Springs, New York

A floating Nordic-style sauna moored on Saratoga Lake, with a 15-person cabin, roof terrace and lake plunge, open daily except Monday.

Los Angeles, California

Four Seasons hotel spa in Beverly Hills with a steam room, rooftop pool, fitness center and eight treatments, open daily, day passes available.

Houston, Texas

A Four Seasons hotel spa in downtown Houston with three treatment rooms, a couples' suite and rooftop pool access, open to day-pass guests.

Chicago, Illinois

Hotel spa inside The St. Regis Chicago with a 12,000-square-foot wellness floor, pool and skyline views above the Loop, open daily 8am–8pm.

Nashville, Tennessee

Hotel spa inside the Four Seasons in downtown Nashville's SoBro district, open to hotel guests, with a rooftop pool over the Cumberland River.