If you are arriving at JFK Airport on an international flight and connecting to any other flight (domestic or international), you must go through U.S. Customs and Border Protection (CBP). Unlike many international hubs in Europe or Asia, U.S. airports do not have a "sterile transit" area for international passengers. This means you will go through immigration (passport control), collect your checked luggage from the carousel (even if it is tagged to your final destination), and clear customs. After clearing, you will immediately find a "Baggage Re-check" counter to drop your bags back off. You will then need to take the AirTrain to your departure terminal and clear TSA security again to reach your next gate. The only exception is if you are arriving from an airport with "U.S. Preclearance" (like Dublin or many Canadian cities), where you clear U.S. immigration before take-off and arrive at JFK as a domestic passenger. Travelers should allow at least 3 hours for this process during peak times.