Roundtrip tickets feel like the responsible choice - same airline, same route, one transaction. But the logic only holds if you actually want to leave from the same city you arrived in, and that assumption quietly wrecks more itineraries than people realise.
If you fly into Lisbon and book a roundtrip back to Lisbon, you’ve already committed to ending your trip in Lisbon. Which means you either rush back from wherever you’ve drifted - Porto, the Alentejo, the Algarve - or you spend your last two days killing time in a city you already covered at the start. Neither is a good use of time or money.
One-way in, one-way out from a different city solves this completely. It lets the trip move in a direction rather than loop back on itself. Fly into Madrid, out of Barcelona. Into Athens, out of Thessaloniki. Into Naples, out of Rome. The itinerary follows geography instead of fighting it.
The price gap is usually smaller than you expect
The assumption is that two separate one-way tickets will cost significantly more than a roundtrip. Sometimes that’s true. But with low-cost carriers - Ryanair, Wizz Air, easyJet - operating dense European networks, one-ways on separate routes are often cheaper than a roundtrip when you factor in the return positioning. If you would have paid for a train or bus back to your arrival city anyway, the maths almost always favour open-jaw routing.
Open-jaw is the industry term for flying into one city and out of another. Most flight search engines support it. On Google Flights, you just enter different cities in the origin and destination fields for the return leg. Skyscanner has the same functionality. It’s not a workaround - it’s a standard fare type.
Visa implications are worth checking
For Schengen travel, an open-jaw itinerary doesn’t create any complications - you’re still entering and exiting the same visa zone. Where it matters is if your open-jaw crosses into a different visa territory, or if you’re travelling on a passport that requires onward travel proof at the border. Some immigration officers want to see that you have a confirmed exit, and a one-way into a country without onward documentation can occasionally cause friction. Carry both booking confirmations.
The bigger point is that roundtrip ticketing is a default, not a rule. Defaults are worth questioning every time you plan a route that has any geographic depth to it.