Guildford Castle is thought to have been built by William the Conqueror, or one of his barons, shortly after the Norman invasion of England in 1066. Used as a Royal Palace, a prison and a private residence, Guildford Castle and grounds was sold to the Guildford Corporation in 1885. The grounds at Guildford Castle opened as public gardens in 1888 to mark Queen Victoria's Golden Jubilee in 1887.

The castle gardens are famous for their vibrant floral displays, centred on the 11th Century Castle Keep. Other attractions include a life-size statue of Alice Through the Looking Glass, a bowling green and music concerts in the bandstand. The town's war memorial stands in the grounds. Open-air theatre takes place in the summer months. Entry fees for visiting the Castle are:

• Under 5's : Free
• Children: £2.50
• Adults: £4.50
• Family Tickets (two adults and two children): £12.00

The Castle Grounds and Castle Cliffe Gardens are open by 9am throughout the year. They close at 7.30pm in summer months and 5pm in winter months.

The Castle keep is open from Saturday 5 April until Saturday 1 November 2025.

Opening hours are Wednesday to Saturday from 12noon to 4.30pm (last admission 4pm).