SeaTac has a population of approximately 31,454 residents, according to the 2020 U.S. Census. The city has experienced steady, modest growth over the last two decades, driven by immigration and the availability of relatively more affordable housing compared to Seattle proper.
SeaTac is one of the most diverse cities in Washington State. A significant percentage of the population is foreign-born, serving as a welcoming hub for refugees and immigrants from East Africa, Latin America, Southeast Asia, and the Pacific Islands. This diversity is reflected in the local school district, where over 80 different languages are spoken by students.
The median age is around 36 years, reflecting a healthy mix of young families and working-age professionals. While many residents are employed in the blue-collar, service, and transportation sectors, there is a growing community of young professionals seeking accessible transit into Seattle.