One-Way vs. Round-Trip Flights: When the Math Actually Favors One-Way
Round-trip is usually cheaper than two one-ways — but not always. Here's when one-way tickets win.
Where one-way wins
On intra-Europe and Southeast Asia low-cost corridors, one-way pricing is the default; round-trip is just two one-ways added together with no discount.
When two different carriers offer the cheapest outbound and return legs, splitting the booking can beat any single carrier's round-trip.
Where round-trip wins (almost always)
On legacy long-haul routes, round-trip fares are heavily discounted relative to two one-ways on the same carrier. Buying two one-ways on these corridors is often 50-100% more expensive than the round-trip.
Open-jaw and multi-city tickets
Open-jaw itineraries (fly into one city, out of another) often price close to a round-trip and save the cost of returning to your starting point. Multi-city bookings on legacy carriers sometimes price similar to round-trips when the segments share a major hub.