I was recently flying from the US to India via Frankfurt. After landing in Frankfurt airport, I was allowed to proceed to my gate to board my next flight. However, on the way back, all passengers on my flight were required to go through security again even though we landed in the international area. What's the reason for doing so? Is this standard procedure when landing in Frankfurt or any Schengen airport from a non-US/EU country?

  • Can you clarify where you went through the additional security check? Was it before you were able to enter the departure terminal, or was it after you were already inside the departure terminal, but before you were able to access the area of that terminal where your gate was? (Both are possible, but the reasons for each will be different)
    – Doc
    Mar 15, 2023 at 6:28
  • It was after I was inside the departure terminal, but before being able to access the gate.
    – Paddy
    Mar 16, 2023 at 23:32
  • In that case, the correct answer is the one from Ozzy - this is a US-specific requirement. If the security was to get into the departure terminal itself, then mlc's answer is correct.
    – Doc
    Mar 17, 2023 at 19:36

3 Answers 3


The EU has a program called "one-stop security", where some countries' aviation security practices are recognized as equivalent to EU standards, so passengers on flights arriving from those countries do not have to clear security again when connecting at an EU airport. Those countries are

  • the United States of America
  • Canada
  • Montenegro
  • Faroe Islands, in regard to Vagar airport
  • Greenland, in regard to Kangerlussuaq airport
  • Guernsey
  • Jersey
  • Isle of Man
  • Singapore

However, implementation of this can in practice be mixed, and some passengers on some flights at some EU airports from some one-stop countries may be subject to security re-screening anyway.

  • That's certainly not happening at CDG
    – Hilmar
    Mar 15, 2023 at 14:30
  • In the case of Frankfurt the problem is the terminal layout. Depending on where your inbound and outbound flights dock you may need to re clear security, but not always. Mar 15, 2023 at 20:53

This is a requirement for US-inbound flights. DHS outlines this reasoning:

....Secretary of Homeland Security John Kelly has determined it is necessary to implement enhanced security measures for all commercial flights to the United States. These measures, both seen and unseen, include enhanced screening of passengers and electronic devices as well as heightened security standards for aircraft and airports.

Countries: 105 Airports: 280 (approximate number as it will vary based on seasonal airports) Total airlines: 180 Average daily flights: 2,100 Passengers: 325,000 average daily passengers

See the link here

  • Unseen security measures? What is the point of security measures if nobody sees the result of the measurement?
    – gerrit
    Mar 14, 2023 at 13:52
  • @gerrit I never said it made sense haha, but it answers the question. Gotta love the US.
    – Ozzy
    Mar 14, 2023 at 14:37
  • 1
    @gerrit, presumably means unseen by the passengers under surveillance, not unseen by security personnel. Mar 14, 2023 at 16:54

That's unfortunately normal. By default all connecting passengers have to go through security and plenty of airports do this for everyone regardless of where you come from (London (LHR), Paris (CDG), Doha (DOH), etc.)

Some airports can choose to skip security if the incoming flight is from a "good" country (which is determined by a variety of criteria). Frankfurt, Vienna, Tokyo Narita, etc. are examples of that.

You can never predict with certainty what's going to happen. We flew EWR<->CGK through Tokyo. On the outbound we just walked from the plane into the Terminal. On the return flight last week we had a totally different experience: First they deplaned all passengers that were entering Japan and held everyone else back on the plane. Only after this we were allowed to get off the plane only to be greeted by a very long security line. I'm fairly sure some people missed their connection that day. No idea why they did that.

  • 1
    Sometimes it depends not only on the country of origin of the flight, but also the specific airport of origin, the airline, or even the specific flight. The rule may also be different between different airports in the same country.
    – jcaron
    Mar 14, 2023 at 15:12

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