When getting the dog accustomed to doing water recalls, retrieves or swimming, it is best to entice him along, parallel to the shoreline. Work together and take turns, and respect everyone else's need to practice in the water, too. There is only so much shoreline, and only so many boats and life jackets, everyone can not use them at once. Practicing in groups and taking turns is the most effective way to get your water exercises done. Remember that during your free time, the beach may not be occupied, and it would be a great time for you and a few friends to get in some beach time.
All dogs know how to swim.
They just don't KNOW that they know how to swim. Do NOT throw your dog into the water to force him to realize that he can swim. Work gradually and build his trust. Think about how terrified you felt when you were just learning to puppy paddle.