Twenty Grosvenor Square

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.