Guess who knows how to swim?
Will has a pretty awesome doggy paddle, but doesn't have a ton of confidence just yet. In order to get him to swim, we stand really close and tell him to come to us; meanwhile we just continue to back up. Yes, this pisses him off, but it's the price we must pay in order to show him that he really does know how to swim.
If you took the time to watch that video, you probably noticed Amelia making a cameo appearance. Like a little fish, she loves to swim.
No helping hands necessary. She swims alone.