Seattle Sounders FC are an American professional soccer club based in Seattle, Washington. The Sounders compete as a member of the Western Conference of Major League Soccer (MLS). The club was established on November 13, 2007, and began play in 2009 as an MLS expansion team. The Sounders played their inaugural match on March 19, 2009, winning 3–0 over the New York Red Bulls. Seattle has been among the league s most successful teams, winning the U.S. Open Cup four times, the Supporters Shield in 2014, and the MLS Cup in 2016 and 2019. The team has qualified for the MLS Cup Playoffs in each of its eleven seasons, making the final three times, and competed in the CONCACAF Champions League five times, advancing to the semifinal round once. The team set a new MLS record for average attendance in each of its first five seasons. The Sounders are ranked as one of the most valuable franchises in North America.