Best Spas in London 2025: Thermal Pools, Hotel Spas & Day Spa Escapes

London's spa scene has evolved from a niche luxury to an essential part of the city's wellness culture — with the thermal pools of Thermae Bath Spa just 90 minutes away, the magnificent hotel spas of Claridge's and The Corinthia, and an increasingly excellent network of neighbourhood day spas making high-quality wellness treatment accessible across every postcode. This guide covers the best spa experiences in and around London.