Seattle-Tacoma International Airport Statistics

Seattle-Tacoma International Airport (SEA) is the primary air gateway for the Pacific Northwest. Each year the airport moves more than 50 million travelers and serves as a critical hub for domestic and international flights throughout the western United States.

Seattle-Tacoma International Airport handles around 50 million passengers annually, and is one of the fastest-growing major airports in the United States.

• SEA processed 52.72 million passengers in 2025, a 0.1% increase from 52.67 million in 2024 and a new record. The total is also 1.7% above the pre-pandemic high of 51.83 million from 2019.
• Traffic fell to 20.06 million in 2020, then rebounded to 36.15 million in 2021

International vs Domestic Passengers

SEA remains primarily a domestic airport, though international demand is rising fast.

• Domestic passengers: 45.61 million in 2025, 86.5% of total traffic, a 1.02% decrease from 2024.
• International passengers: 7.11 million in 2025, 13.5% of total traffic, up 7.9% year over year

Inbound vs Outbound Passengers

SEA functions mainly as an origin-and-destination airport, producing almost identical inbound and outbound volumes.

• Inbound passengers in 2025: 26.4 million (22.82 million domestic, 3.58 million international)
• Outbound passengers in 2025: 26.32 million (22.79 million domestic, 3.53 million international)

Alaska Airlines dominates passenger traffic at Seattle-Tacoma International Airport.

• Alaska Airlines handled the most passengers, with 22.44 million travelers in 2025 and a 42.6% market share.
• Delta Air Lines followed: 10.39 million passengers and 19.7% of the market.
• Horizon Air served 2.92 million passengers, while United Airlines and Skywest, operating as Delta Airlines carried 2.68 million and 2.33 million passengers, respectively.

Seattle-Tacoma International Airport offers connectivity with 129 total destinations, comprising 94 domestic and 35 international routes served by 37 airlines.

Domestic Destinations

• Anchorage (ANC) was the most frequently served domestic destination at 1.02 million passengers in 2024.
• Los Angeles (LAX) was the destination for 983,250 passengers.
• Las Vegas (LAS) ranked third (951,140 passengers).
• Denver (DEN) and Phoenix (PHX) completed the top five with 950,210 and 944,730 passengers respectively.

International Destinations

• Vancouver, Canada (YVR) led international destinations at 668,816 passengers in 2024.
• London, United Kingdom (LHR), and Incheon-Seoul, South Korea (ICN), ranked next with 524,399 and 504,758 travelers, respectively.
• Taipei, Taiwan (433,653) and Charles de Gaulle, Paris, France (320,173) complete the top five international destinations.

• On-time departures: 78 % in 2024 (down from 82 % in 2023).
• On-time arrivals: 79 % in 2024 (down from 83 % in 2023).
• Average departure delay: 54.72 minutes, an improvement over 57.03 minutes in 2023
• Average arrival delay: 58.18 minutes, better than 61.59 minutes in 2023
• Cancellation rate: 1.11 % in 2024, up from 0.60 % in 2023