If it’s your first time visiting a foreign city, you may want to pay close attention to where that flight is actually landing. In some world capitals, even the main airport is a long hike from the center, especially Narita for Tokyo and Seoul’s shiny airport, which is more than an hour away by bus or train, in Inchon.

The big problem though is when your flight to, say, Paris isn’t going to the Paris airport. Last month Budget Travel magazine ran an article on where some of those budget European flights land and how long it’s going to take you to get to the city center from them.

For example, that Air Berlin, RyanAir, or EasyJet flight to London will actually land 32 miles away at Stansted. The train to Liverpool Street station takes 45 minutes and will cost you 21 pounds—about $33.

A Wizz Air flight to Munich is actually touching down in Memmingen, 63 miles away. It’ll cost you almost 30 euros to take the express bus to the city.

Going to Barcelona? The budget airlines flights marked as such actually go to Girona, which is 62 miles away. The 75-minute bus ride after you get your luggage will cost 12 euros.

Most of Latin America is not developed enough that this is an issue—budget airlines are a rarity outside of Brazil and Mexico. The big one to watch out for though is Mexico City. Many airlines (including Spirit and similar Aerobus) fly to Toluca instead, which is an hour outside the city on a good day with not much traffic. The public transportation options are very limited too even if your Spanish is good.

Sometimes this extra hike can be worth it if the fare is low enough after factoring in all the extra fees. Or if you’re on some kind of package tour where you’re all piling into a vehicle together, then no worries. Otherwise, you’ll need to run the numbers with a calculator to see if the savings add up.

Have you gotten an unwanted surprise when traveling to a foreign city?