The Lisbon Airport web site recommends that, even if you have checked in online or have your boarding pass, you should return to the airport no less than 90 minutes before your onward flight (although, with the size and layout of the facility, 75 minutes should be adequate).
It even suggests a visit to the city center during a long layover, and offers to hold on to any baggage.
How far in advance do I need to check-in?
The recommended check-in time varies depending on the flight. In order to avoid delays and make the most of your pre-boarding time, please respect your airline's minimum check-in time. That way, you also avoid the risk of arriving after check-in closes:
At the Airport's check-in desk:
- Schengen flights: 90 minutes
Schengen regulations have removed controls at the internal borders of signatory states: Germany, Austria, Belgium, Denmark, Slovakia, Slovenia, Spain, Estonia, Finland, France, Greece, Holland, Hungary, Iceland, Italy, Latvia, Lithuania, Luxembourg, Malta, Norway, Poland, Portugal, Czech Republic, Sweden, Switzerland.
- Non-Schengen flights (Europe): 120 minutes
- Flights to Third Countries (Intercontinental): 180 minutes
For most airlines, check-in can be made online 48 hours prior to boarding – check the recommended check-in time with your airline in advance.
Flights to the United States and Switzerland - 24 hours
Remember that, after checking-in, you will have to go through X-ray screening and, when travelling to non-Schengen destinations, you must also go through passport control. Therefore, avoid delays and plan your arrival at the airport in advance.