Visiting the interior of Windsor Castle is not free; it is a paid ticketed attraction managed by the Royal Collection Trust. As of 2026, adult tickets typically cost around £30 to £33, and it is highly recommended to book in advance online to secure a specific time slot, as the castle frequently sells out. Your ticket includes access to the State Apartments, the Semi-State Rooms (when open), St. George's Chapel (where Queen Elizabeth II is interred), and Queen Mary's Dolls' House. However, you can see the exterior of the castle and witness the Changing of the Guard for free from the public streets of Windsor town. Additionally, the Long Walk and Windsor Great Park are free to the public and offer spectacular views of the castle's silhouette. If you are a resident of the Royal Borough of Windsor and Maidenhead and hold an "Advantage Card," you may be eligible for free entry, but for the vast majority of tourists, a paid ticket is the only way to step inside the world's oldest and largest occupied castle and explore its nearly 1,000 years of royal British history.