Overview
Twenty Grosvenor Square is a residential conversion at 20–21 Grosvenor Square, Mayfair, W1K, developed and designed by Finchatton with architecture by Squire & Partners. The former European headquarters of the US Navy — built in the 1930s — was converted into 37 private residences and opened in 2019 as the world's first standalone Four Seasons Private Residences building.
The 37 apartments and penthouses are configured as three, four, and five-bedroom homes, each incorporating classical drawing rooms, high ceilings, and professional kitchens. The building offers a 25-metre swimming pool, spa with steam room and sauna, state-of-the-art gym, cinema, wine cellars, children's playroom, business suite, garden library, and 24-hour concierge with valet parking. The facade combines brick, stone, and contemporary metalwork, with a double-height entrance and glasswork by Czech artists Lasvit.
Key details
Status
Available
District
Mayfair (W1K)
Address
20-21 Grosvenor Square, London W1K 6LE
Completion
Ready to move
Amenities
- Concierge
- Gym
Location
20-21 Grosvenor Square, London W1K 6LE
Key highlights
Zone 1 London location - Mayfair (W1K)
Walking distance to Bond Street, Green Park and Hyde Park
Developer: Finchatton
Amenities: 24hr concierge, residents' gym
Architecture by Squire & Partners; interiors by Finchatton
37 residences in a converted 1930s US Navy headquarters building
World's first standalone Four Seasons Private Residences, opened 2019
25-metre swimming pool, spa, cinema, wine cellars, and gym
All development references on this site are for general market information only. Prime Legacy Homes acts as an independent buyer advisor and does not act as the selling agent for any named development unless formally instructed in writing.
Want a shortlist tailored to you?
Tell us your budget, areas, and timeline - we’ll respond with a clear plan and next steps.