Using this for windsurfing. Keeps me warm and dry! It doesn't breath, but I dont find any problems with this as I only surf slalomboards with this suit. For waves I always use a wetsuit. Even a drysuit that breaths wont get all the sweat out when you go wavesailing. So superhappy with the suit! Really comfy and really cheap compared to all other suits. The thermal undersuit is a must, so when it condensates inside the suit, you wont feel this at all!