Booking a flight involves navigating a maze of decisions. Is it better to fly with a budget airline or full-service one? How about basic economy versus regular economy? And would you prefer pretzels or a cookie?
Choosing between a single round-trip or two one-way tickets is the most basic decision and — you might be surprised to learn — one of the more nuanced.
The cost between the two is usually the same for domestic flights but can vary significantly for international routes.
Given that airfare was 26% more expensive in January 2023 than January 2022, according to the latest consumer price index data, budget travelers need to save every penny they can.
In general, it can be more convenient to book a round-trip flight for a trip with specific start and end dates, but other considerations, such as cancellation policies and pricing, could make booking one-ways more appealing in some cases. And everything works differently for flights booked with miles.
Let’s break it down.
For flights within the United States on the same airline, round-trip tickets almost always cost the same as two one-ways.
There’s one caveat here: Booking two one-way tickets between separate destination or arrival airports can, in some cases, save money (or cost more).
“Fares don’t have to be booked as returns,” says Laura Lindsay, travel trends expert at SkyScanner, a travel booking platform. “Look at flying out with one airline and back with another, or out of one airport and back into another to save money.”
Many online travel tools will automatically compare prices for these mismatched airline or airport itineraries and automatically include them in search results.
But it might be worth checking manually, especially for plans that involve different local airports or for airlines that don’t appear in search results, such as Southwest.
All that said, for domestic flights, the difference is almost always a wash.
For international tickets, the logic changes completely. Round-trip tickets are usually cheaper than one-ways, sometimes significantly so.
NerdWallet compared fares across multiple international routes and found that, typically, buying two one-way tickets costs 20% more than a single roundtrip.
To determine these differences, we compared routes between four U.S. airports and two airports in each destination region.
The effect is more pronounced when flying to some regions, such as Africa and Asia. That said, for flights between the U.S. and every region we looked at, it costs more to book two one-ways than a single round-trip.
In some circumstances, such as open-ended trips where you don’t know when you’ll be returning, one-way flights might still make the most sense. But for most international travel, round-trip fares are the clear winner.
Are round-trip or one-way flights cheaper if booking with points?
What about the cost difference between one-way and round-trip fares when using points or miles?
Generally, airlines break these fares into one-way sections, meaning there is no meaningful difference between the two, in terms of cost. Yet a few caveats apply:
Taxes on award flights can be higher when booking two one-ways. Delta Air Lines, for example, tends to charge more fees for flights originating in Europe.
Some airlines, such as ANA, do not allow one-way award flights, period.
Flights booked with credit card points using a travel portal (i.e. not transferred to an airline partner) follow the same rules as cash fares.
It’s also worth considering the impact of changes and cancellations on the two options.
Most airlines have eliminated change fees, making it easier to change and cancel both kinds of tickets. But canceling one leg of a round-trip ticket can sometimes be more complicated than canceling a one-way ticket.
In some cases, you might need to call customer service, instead of canceling online, to make sure the change doesn’t cancel your other flight segments as well.
And finally, there’s the question of simplicity.
Is the simplicity of having a single itinerary, managed by one round-trip confirmation code, worth these other trade-offs? This simplicity, paired with the fact that round-trip tickets are almost never more expensive than two one-ways, means that these fares make sense for most travelers.
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Sam Kemmis writes for NerdWallet. Email: email@example.com. Twitter: @samsambutdif.