Boo! Seattle is Insomniac's two-night Halloween takeover of downtown Seattle's WaMu Theater — returning October 30–31, 2026 for a costume-mandatory celebration of bass, house, trance, dubstep, tech house, and drum & bass. The festival has been a Pacific Northwest Halloween tradition since 2014 and consistently sells out both nights. WaMu Theater's indoor environment makes Boo! the rare Insomniac event that runs rain-or-shine, perfect for late-October Seattle weather.
The 2026 Boo! Seattle lineup brings the deeper Insomniac roster — heavy on bass, dubstep, and trance with house and tech-house balancing the program. Both nights run as fully-themed Halloween parties with elaborate stage production, immersive Halloween décor, and the costume culture that defines every Insomniac Halloween event. Expect surprise B2Bs, headliner set extensions, and the kind of dancefloor energy that PNW Headliners save up all year for.
WaMu Theater is downtown Seattle's 7,500-capacity indoor venue, located right next to Lumen Field and a few blocks from the light-rail. The indoor setting, the downtown location, and Insomniac's production scale combine into a Halloween experience that's significantly larger and more produced than a typical club night but still intimate enough that you can find your friends and feel the headliner energy from anywhere in the room. This is the Halloween festival Pacific Northwest Headliners build their costumes for.