Spas with adults only

Spa, Liège

Thermal baths in the town of Spa, Belgium, fed by natural mineral water, with saunas, hammams and separate textile and naturist relaxation areas.

Rogaška Slatina, Savinjska

Wellness center at Grand Hotel Rogaška in Rogaška Slatina, Slovenia, with pools, saunas and fitness; day pass available by reservation.

Rotorua, Bay of Plenty

A Rotorua day spa built around Ngāti Whakaue hot-springs traditions, centered on a seven-step geothermal Restorative Journey with lakeview thermal pools, mud

Brežice, Posavje

A large thermal water park in Brežice, Slovenia, with a year-round indoor pool riviera, an adults-only sauna zone, and seasonal outdoor slides.

Asheville, North Carolina

A day spa in a converted barn on Horse Shoe Farm near Asheville, offering massage and body treatments amid farm and mountain surroundings.

Jemez Springs, New Mexico

Walk-in outdoor mineral hot springs in Jemez Springs, NM, with four pools kept between 98 and 105°F and a $25 one-hour day pass.

Miami, Florida

A large hotel wellness resort on North Beach with a European-style hydrotherapy circuit, cryotherapy, acupuncture and an oceanfront fitness center.