Open jaw flights (the name really paints a picture) is used for connections that are not a closed route. In other words: you will depart from an airport, but arrive at a different one. Or the other way around.
Example
The first segment of your itinerary will take you from Stockholm to Madrid. Since you have a friend who lives there and you want to visit his cousin in Barcelona, you decide that your flight back to Stockholm should leave from there. So, this is how your route will look like:
Double open jaw
This is the next step you can take. Instead of three airports, like in our example above, you will include four airports. To stick with our idea from before: you wouldn’t even fly back to Stockholm but to Gothenburg.
How to use open jaw flights to save money
The great thing about open jaw flights isn’t just the flexibility they offer. The can also save you a lot of money. By picking different airports for departure and arrival, you can save fuel surcharges or other taxes.
How to book an open jaw flight
You can search for open jaw flights using Google Flights. Just choose the ‘Multi-city’ option.
Also, most OTAs will allow you to book open jaw flights. The system is the same as with Google Flights. Let’s have a look at Expedia for example: