Set up booth spaces for vendors and volunteers. Use the computer to check in runners and register kids for fun run. Hand out shirts to runners and volunteers. Give runners directions for things like toilets and bag check. Set up water stations and hand out water or electrolyte drinks. Course marshals keep folks on course and help to identify injured runners for medical staff. Break down start and finish line.
Volunteer needs vary from setting up, checking in runners at the start line, registering kids for the fun run, and managing gear check to being on the course at the water stations and serving as a course marshal (keeping people on course).
Email volunteer@seattlemarathon.org or register to volunteer at seattlemarathon.org/volunteer