The process for international arrivals connecting to other flights
International flights (other than Canadian pre-clearance) arrive and process at the S Gates. All passengers must be interviewed by U.S. Customs and Border Protection and claim all checked luggage before being allowed to enter the U.S.. Once cleared by CBP, passengers will have the opportunity to recheck their luggage for a connecting flight, or exit the airport locally.
Note: All liquids, gels and aerosols in containers larger than 100 mL (3.4 ounces) including Duty Free, are PROHIBITED in carry-on luggage when proceeding through the passenger screening. Certain exceptions apply regarding medications and breast/baby milk.
After passenger screening, travelers will then use the Subway Transit System for connections in other terminals.
Traveling with a tight connection
Sea-Tac Airport does utilize an Express Connection Program, that allows airlines to identify passengers with tight connections to speed their process. Check with your airline representative once you deplane.
*TSA Pre-Check is located only at main terminal checkpoints*