It depends. Whether you need to clear customs during a layover comes down to where you’re flying, how the airport is set up and your travel plan.
United States and Canada 🌎
If you’re landing in the US or Canada from another country, you’ll always clear customs and immigration at your first stop, even if you’re just passing through. This means you’ll need to show your passport, grab your luggage, check it back in, and go through security again before boarding your next flight.
Europe and the Schengen Area 🌍
In Europe, it’s all about whether you’re travelling inside or outside the Schengen Zone. If your flights stay within the Schengen Area, you usually won’t need to deal with customs on your layover. But if you’re entering or leaving the Schengen Zone, you’ll clear immigration at the first or last point of entry.