London Buses operates a bus from Chessington to Windsor Castle every 5 minutes. Tickets cost $3 and the journey takes 24 min. 4 other operators also service this route.
How to get from Chessington to Windsor Castle
From Hook, Mansfield Road (KT9) bus to Cromwell Road Bus Station, bus to Elmsleigh Bus Station, line 8 bus to Windsor Town Centre, WH Smith (Central Station Access Road), then walk to Windsor Castle. 2 h 17 min £14. From Chessington taxi to Windsor Castle. 31 min £108. From Chessington drive to Windsor Castle. 31 min £4.