"The weeklong strikes by 374 workers at the DoubleTree by Hilton Hotel Seattle Airport and Hilton Seattle Airport & Conference Center will last until the early hours of Oct. 19," the union said.
"We remain committed to negotiating in good faith to reach fair and reasonable agreements that are beneficial to both our valued team members and to our hotels," a Hilton spokesperson said in an emailed statement to Reuters.
A total of over 4,300 hotel workers are now on strike at Hilton, Hyatt, and Marriott hotels in Honolulu, San Diego, San Francisco and Seattle.
Around 2,000 workers walked off the job in September at Hilton's largest hotel in the world, the Hilton Hawaiian Village in Honolulu.
Some 10,000 US hotel workers began a multi-day strike in several cities during the Labor Day weekend after contract talks with Marriott, Hilton, and Hyatt stalled.