Spas with reservation required

The Hamptons, New York

A moderate-priced, adults-only day spa in Hampton Bays focused on massage, with a salt room and red light therapy, by appointment only.

Calistoga, California

MoonAcre Spa & Baths is a day spa in Calistoga with a thermal pool, hot tub and sauna, open daily 9am–5pm and geared toward families and couples.

Bad Blumau, Styria

Rogner Bad Blumau is a Hundertwasser-designed thermal resort in Styria with geothermal pools, outdoor baths and hotel-guest-only access.

Miami, Florida

Recovery and longevity studio in Brickell offering sauna, cold plunge, cryotherapy and IV therapy, bookable by reservation or walk-in.