Get Off at Hyde Park Corner (near Buckingham Palace)
Bus No. 36 and 436 from Paddington Station
Bus No. 73 From King Cross and Euston Station
Bus No. 14, 19, 22, 38 from Angel via Picaddily Circus
Bus No. 2, 9, 16, 52, 74, 82, 414, 148 and 137 also passing through Hyde Park Corner.
Hyde Park Corner Station on Picaddily Line (use exit 4 or 5) and going south until you get to Grosvenor Cresent and follow this road which will lead you to Belgrave Square
Victoria Station on Victoria, Circle and District Line (use exit to Buckingham Palace Road) and going northbound onto Grosvenor Place and Hyde Park Roundabout take 1st exit on the left onto Grosvenor Cresent which will lead you to Belgrave Square.