The Redhawks (3-4) had one player in double figures, Isiah Umipig, with 10 points. Seattle hit just 17 of 53 shots for 32.1 percent, making only 5 of 20 from beyond the arc.
The Gauchos sped to a 27-8 lead over the first 9 minutes of the game and led 49-19 at halftime.
Seattle, which opened with five games at home and then another in nearby Kent, Washington, had a two-game win streak snapped.
UC Santa Barbara has won four of its last five games.