The Northwest Seaport Alliance, a partnership between the Puget Sound ports of Tacoma and Seattle, said year-to-date container volumes were up 10 percent compared with the previous year.
In a news release, the alliance said international volumes recorded the highest first quarter since 2005.
The alliance moved 351,607 TEUs, or 20-foot equivalent containers, in January, February and March in full imports.
Breakbulk cargo, items not shipped in a container, was down 16 percent year to date because of soft market conditions, to 38,114 metric tons.
March was the fifth-largest month for autos in the past 21 years. Autos reached 44,317 units year to date and were flat compared with the first quarter of last year.
Log volumes climbed more than 76 percent to 62,573 metric tons compared with March of last year because of demand from China.
The Seaport Alliance is the fourth-largest container gateway in North America by volume.