Spas with reservation required

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.

Phuket

Adults-only Ayurvedic resort on a Rawai hillside with doctor-led Panchakarma programs, a saltwater pool and 47 private villas.

London, England

A Russian-style banya bathhouse in Belgravia offering oak-lined steam rooms, cold plunge pools and leaf-massage rituals, with day passes by reservation only.

Kandy, Central Province

An adults-only Ayurvedic retreat in the hills above Kandy, Sri Lanka, with overnight stays, yoga and a restaurant, but no day-pass access.

Asheville, North Carolina

Ayurvedic destination retreat in the Blue Ridge Mountains near Asheville, with day-pass spa visits and multi-night panchakarma cleanses by reservation.