Mukilteo T-Dock (Lighthouse Park)

A long-running training and night-dive site beside the Mukilteo ferry terminal and Lighthouse Park, entered from the beach next to the Silver Cloud Inn. A gradual sand slope passes pilings and placed attractions - most famously a PVC-pipe geodome at roughly 50-70 ft - and keeps dropping past 100 ft, making it popular for deep and tech training as well as open-water classes. The original T-shaped dock was removed during ferry terminal construction in the mid-2010s, but the geodome, debris reef and abundant critters remain.