This is a truly unique spot in the Pacific Northwest. It is a long sandy beach that you can wade out into Puget Sound for a hundred yards and the warm water is still only waist deep. You could also spend time here exploring the island, but the sand was too dang hot for that on our trip.
It was a whopping twenty degrees cooler here than at our house in the Cascade foothills where it felt like a giant blow dryer was trained on us.
This is a fantastic outing for family fun. The kids love the novelty of the four minute ferry ride and the danger quotient is extremely low. They can just run and splash and wear themselves out. If you have puppies for children like I do, it's a perfect spot. For such a hot day, it was surprisingly not too crowded, though I suspect that changes on summer weekends. I highly recommend it. The ferry is free, but donations are suggested to help subsidize the ferry at $2 per adult and $1 for children, round trip.