To experience Sintra in 2026 without being overwhelmed by crowds, you should aim to arrive by 8:30 AM, or even earlier if taking the train from Lisbon. Most major monuments, like the Pena Palace and the Quinta da Regaleira, open at 9:00 AM or 9:30 AM. Arriving early allows you to visit the most popular site (usually Pena Palace) before the massive tour groups arrive at 11:00 AM. Alternatively, a "late" visit starting around 3:30 PM can be effective, as many day-trippers head back to Lisbon by late afternoon, leaving the town's misty, romantic streets much quieter. Avoid weekends and Mondays if possible, as these are peak days. Pro tip: pre-book your Pena Palace time slot weeks in advance, as the strict entry times in 2026 mean walk-up tickets are almost non-existent during high season.