While you could spend weeks exploring Portugal, 3 full days in Lisbon is widely considered the "perfect" amount of time to see the city's primary highlights without feeling overly rushed. A typical 2026 itinerary would dedicate Day 1 to the historic center, including the Alfama district, São Jorge Castle, and a traditional Fado dinner. Day 2 is best spent in the Belém area to visit the Jerónimos Monastery, the Belém Tower, and the famous Pastéis de Belém bakery. Day 3 is almost universally reserved for a day trip to the fairytale town of Sintra (a 40-minute train ride) to see the Pena Palace and the Quinta da Regaleira. Because Lisbon is a compact and highly walkable city with an efficient tram and metro system, you can cover a significant amount of ground in 72 hours. However, if you want to include a beach day in Cascais or visit the Arrábida Natural Park, you would need to extend your stay to 4 or 5 days.