Lisbon to Denver (LIS–DEN) — Airlines, Schedules & Connections

Portugal is part of the US Visa Waiver Program. Portuguese passport holders enter the United States for up to 90 days without a visa, but must obtain an approved ESTA (Electronic System for Travel Authorization) before boarding. The ESTA costs USD 21, is valid for 2 years or until the passport expires, and covers multiple entries. Apply at the official CBP site (esta.cbp.dhs.gov) at least 72 hours before departure.

The 90-day stay cannot be extended, and you cannot change immigration status while in the US on the Visa Waiver Program.

Metro Red Line runs from downtown Lisbon (Alameda, Oriente) to the airport in 20–25 minutes (€1.85 single, or €0.48 on a Viva Viagem card). Trains run from 6:30am to 1am. The airport has its own station (Aeroporto) at the end of the Red Line.

Taxis from central Lisbon cost €10–15 and take 15–20 minutes with no traffic. Uber and Bolt are widely available at similar or lower prices. AeroBus (Carris) is slower (30–40 min) but cheaper at €4.

RTD A Line runs to Denver Union Station (37 min, $10.50) with connections to light rail and bus routes. Taxis have meters; expect $55–65 to downtown.DEN's tent-roof Jeppesen Terminal is a single building; all three concourses connect via the underground automated train. Rental cars are on level 5. For ski resorts, shuttle services depart from Ground Transportation.

Semi-arid with 300+ days of sunshine. Summers are dry and warm (27–34°C) with afternoon thunderstorms that produce dramatic but brief delays. Winters bring cold temperatures (−8 to 5°C) and heavy blizzards that can shut down ground operations.

Spring snowstorms can be heavier than midwinter ones. Altitude (5,430 ft) means low humidity year-round; stay hydrated.