The race starts on Mt Baker with the first 2 legs cross-country and downhill skiing, handing off to running to road biking, next canoeing on the Nooksack River, to a mountain bike leg, ending up with kayaking into the finish line in Fairhaven.
There is an extensive spectator guide on the Ski to Sea website and an abbreviated version from the Bellingham Herald
“SPECTATOR HOT SPOTS
• Best place to watch cross-country, downhill ski/snowboard and run: Main Lodge at Mt. Baker Ski Area to see the handoff from the cross-country skiers, a long line of climbers hiking uphill for the downhill ski/snowboard portion and then, a few minutes later, see them speeding down the slope to hand off to the runners.
• Best place to watch road bike leg: Kendall, as bicyclists turn off the Mount Baker Highway onto Kendall Road, or the exchange point with canoeists at the end of the leg at Riverside Park in Everson.
• Best place to watch the canoe leg: Any of the bridges over the Nooksack River between Everson and Ferndale; some beaches near the Guide Meridian and Hannegan bridges.
• Best place to watch mountain biking leg: Marine Drive trail system near the end of the leg.
• Best place to watch kayak leg: The finish line at Marine Park in Fairhaven. But there’s also plenty of viewing possibilities at the start at Zuanich Point Park, the Bellwether, Boulevard Park and the trails and street above Boulevard Park.”
The Big Party is where “it all end’s in Fairhaven”