We take the dogs up to my cabin every summer, and our place is on the lake. Micki used to absolutely HATE the water, he wouldn't even wade. I sat down on the shore one day and started breaking off pieces of treats and throwing them in the water. I started throwing them right at the edge and slowly making it so he had to go in deeper in order to get the food. I never forced him to go in the water, and I did this over several days until he was comfortable going out. He will willingly wade now, but he won't swim and I don't think he will ever actually enjoy swimming.

When Shadow was a puppy my dad forced her to swim. She absolutely HATES the water now and won't have anything to do with it and I believe it had to do with her first (traumatic) experience. I would try to make swimming a happy, enjoyable experience and your dog might learn to at least tolerate the water!