Which airport code refers to Seattle / Tacoma, Washington?

The airport code that refers to Seattle / Tacoma, Washington is SEA. This code is derived from the names of both cities: Seattle and Tacoma, which are located in close proximity to one another and share a major international airport, Seattle-Tacoma International Airport. The use of the first three letters of "Seattle" effectively makes this code easy to remember and recognize, highlighting its geographical significance.

In comparison, the other airport codes listed do not relate to Seattle / Tacoma. STX represents Henry E. Rohlsen Airport in the U.S. Virgin Islands, BDA stands for L.F. Wade International Airport in Bermuda, and GRU is the code for São Paulo/Guarulhos–Governador André Franco Montoro International Airport in Brazil. Understanding these codes requires familiarity with geographic locations and major airports, which makes SEA distinctively associated with Seattle and Tacoma.