What Is an Open-Jaw Flight? How to Book Multi-City Award Tickets

An open-jaw itinerary flies into one city (such as London) and returns home from a different city (such as Rome)—saving 6 to 10 hours of backtracking travel and up to $233 in UK Air Passenger Duty taxes at the same mileage price as a standard roundtrip.

Picture a classic 10-day European itinerary starting in London, taking the Eurostar under the English Channel to Paris, and riding high-speed rail south to Rome. If you book a traditional roundtrip flight into and out of London Heathrow (LHR), you are forced to sacrifice the final day of your vacation buying an extra intra-European flight back to London, hauling luggage through two extra security checkpoints, and paying a steep UK luxury departure tax just to catch your flight home.

In airline ticketing and credit card award travel, the solution is an open-jaw ticket: a single multi-city itinerary where you fly from Home (A) to Destination 1 (B), travel overland on your own to Destination 2 (C), and fly home from C back to A. When plotted on a map, the two flight lines form an angle with an unflown gap between the two cities—looking like an open mouth or jaw.

Three Types of Open-Jaw Routings (and the IATA Shortest-Side Rule)

Airline tariff engines recognize three distinct open-jaw structures:

1. Destination Open-Jaw (Most Common): You fly out of New York (JFK) to London (LHR), travel by train to Rome, and fly Rome (FCO) back to New York (JFK).
2. Origin Open-Jaw: You depart from New York (JFK) to Tokyo (HND), and return from Tokyo (HND) to San Francisco (SFO).
3. Double Open-Jaw: Both ends are open—for example, flying Boston (BOS) to Dublin (DUB) and returning Paris (CDG) to New York (JFK).

Why use the Multi-City tab to book an open-jaw instead of buying two separate one-way cash tickets? Because on transatlantic and transpacific routes, legacy airlines heavily penalize cash one-way fares (often charging 75% to 90% of a full roundtrip price for a single one-way leg). When you book an open-jaw on a single ticket, the airline prices each leg at 50% of the roundtrip fare—provided you obey the IATA Shortest-Side Rule: the unflown surface gap between City B and City C must be shorter in mileage than both of your flown segments (for instance, the 890-mile gap between London and Rome is much shorter than the 3,450-mile flight across the Atlantic).

Always fly INTO London and OUT of continental Europe: the UK's punitive Air Passenger Duty (£105 to £261+) applies only to departures from British airports, never arrivals.

The UK Air Passenger Duty (APD) Arbitrage

When booking with airline miles or transferable credit card points, most modern loyalty programs (such as Air Canada Aeroplan, United MileagePlus, Air France-KLM Flying Blue, and American AAdvantage) price one-way awards at exactly half of a roundtrip—allowing you to build an open-jaw simply by booking two separate one-way awards or using the Multi-City tool.

Crucially, the direction of your open-jaw can save you hundreds of dollars in mandatory government taxes. The United Kingdom levies the highest departure tax in the world—Air Passenger Duty (APD), which adds roughly $135 (£105+) in economy and $320 (£251+) in business class on long-haul departures from London. Because APD is charged strictly on departures from UK airports and never on arrivals, flying into London and home from Rome, Paris, Madrid, or Dublin cuts your award taxes from $318+ down to ~$112 per ticket. You can Compare award tax valuations on Pointsuno to calculate net cents-per-point returns across multi-city itineraries before transferring your points.