Spas with membership available

Portland, Oregon

A member-run bathhouse in Concordia with a clothing-optional salt-water hot pool, cedar sauna and courtyard, day passes from $18.

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.

San Diego, California

Beachfront hotel spa at the Catamaran Resort in Mission Beach offering massages, facials and nail services with a view of Mission Bay.