As of 2026, you cannot generally buy Pena Palace interior tickets at the door for immediate entry. Due to its status as one of Portugal's most visited sites, the park has implemented a strict online-only, timed-entry system to manage overcrowding. You must purchase your ticket (approx. €20) for a specific date and a specific 30-minute time slot well in advance via the official Parques de Sintra website. If you arrive without a reservation, you may find that all slots for the day are sold out. However, you can still buy "Park-only" tickets on-site, which grant access to the sprawling gardens, the terraces, and the Chalet of the Countess of Edla, but not the interior rooms of the Palace. Note that for 2026, "no late arrivals are allowed"—if you miss your specific time slot, your ticket will be forfeited without a refund. It is recommended to arrive at the park entrance at least 30 minutes before your scheduled palace entry time.