So far as wetsuits go theres at least a couple of surf shops local, ones around the corner frome the pond if you follow safety bay rd into shoalwater from the roundabout at the yacht club then take a right onto Rae rd. (seabreeze I think its called

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the nearest windsurfing shop where you would be able to pick up both a weed fin and a spring suit in one hit is probably windsurfing perth up in Myaree on Hulme Ct. theyve got a fairly big range of 2nd hand fins there as well as new, and wetsuits too.
Safety Bay Windsurfing Club have got their opening day and windsurfing gear swapmeet on at the Carlisle St boat ramp tomorrow too. you might get lucky and find a suitable weed fin there, not to mention meeting all the lucky locals too. Theyre all pretty friendly down there, they'll help you out as best they possibly can.....