According to Today.com, basset hounds, bulldogs, dachshunds, pugs, corgis, Scottish and Boston terriers, and greyhounds either do not swim at all or are typically poor swimmers. Although some are able to learn to swim, many are never comfortable in water.
Teaching a dog to swim takes a great deal of patience, and Today.com offers several tips. Lessons should be conducted in quiet and calm surroundings to encourage focus. Dogs learning to swim should be rewarded with praise and treats. Reluctant dogs should never be forced or thrown into the water but gradually coaxed. While a dog is learning to paddle, the owner should hold up the animal's middle and back end to keep it afloat, even if the dog is wearing a flotation device.