Oddly, I have found that the best bet are armbands. Even Chinese ones. We tried every other device you could think of. Amazingly I found the "Bodyglove" swimmers with built in floatation downright dangerous. It actually made Daisy roll and pitch like a barrel and then she would turn turtle with just her legs poking above the water! It makes you wonder if they actually ever tested it out. Armbands don't restirct movement, make kids float the right way around and as the kids gain confidence so you can let the air out, little by little without them even noticing.