I took the train to Swanbourne, and this is what the main street looks like. I went into the shop and asked where the beach was, and got directions. It was quite a walk, but I enjoyed it. Luckily before I set off, the lady in the shop happened to mention that when I got to the beach, Swanbourne Beach was to the right and Cottesloe Beach was to the left, and that Swanbourne Beach was a nudist beach. So naturally I turned left.
This is Swanbourne Beach. The secluded nudist area is apparently behind the rocks. I turned left and walked along Cottesloe Beach.
The only things I stripped off were my shoes and socks, and rolled my trousers up to my knees, and walked on the shoreline. But the first wave got my trousers truly soaked, and after that I gave up trying to keep them dry.