Yes, you generally have to pay an entrance fee to visit the Castelo de São Jorge in Lisbon, as it is one of the most popular historic sites in Portugal. As of 2026, the standard adult ticket price is typically around 15 euros, though there are significant discounts available for students, seniors, and families. Residents of the Lisbon municipality can often enter for free, provided they show proof of residency. The ticket grants you access to the castle's fortified walls, the archaeological site which contains remnants of 7th-century BC Moorish quarters, the "Camera Obscura" which provides a 360-degree real-time view of the city, and the museum. While the cost may seem high compared to some other local landmarks, the panoramic views of the Tagus River and the Alfama district from the castle's ramparts are widely considered the best in the city. It is highly recommended to book your tickets online in advance to skip the long queues, especially during the peak summer months when the sun can be quite intense while waiting at the gate.