We think the Ion harnesses run about 1/2 size bigger than the Dakine. So if you are a tight fit in a Dakine large, you will be a comfortable fit in an Ion large.
Ion CS Freestyle Waist Harness
Windsurf like Gollito Estredo with this Composite Series (CS) Freestyle windsurfing waist harness! Okay, well maybe you won't windsurf just like him...but you can absolutely look great and feel extremely supported with the carbon composite construction and cushy EVA foam lining the interior. The composite gives a strong and reactive feel in the center then tapers out near the sides so you can count on amazing back support and just the right amount of flexibility on the sides. This harness comes with the high performance pre-shape of hyper foam and 3D EVA shape lock to provide an ergonomic fit with minimal friction. The CS Freestyle windsurf harness also features Ion's C_Bar-a fiber reinforced injection molded material around the spreader bar and a tension lever that tightens the harness so you don't have to mess with the side buckles once you get it dialed.
In essence, this harness is super comfortable, extremely supportive, looks great, and is a new shop favorite here at North Beach Windsurfing!