LOL I used Lil swimmers when DS was little. But I don't think they make small enough one's for infants. Good question. I guess you take them in the water and wait till they become so heavy and then switch the diaper. LOL.
They make a swimmer bottom...that is cloth on the outside and plastic on the inside. These are very tight andyou can place on the baby. I found it very hard to get on and off. I just ended up using the swimmers and through them away after we go done in the water. These go on like panties and you are tear them on the sides when you take them off. I just put a bathing suit over it.
I do all of the above (lil swimmers disposables, swimsuit built-ins, reg diapers until they explode..etc..). I've thought a few times about her going swimming bare-bottom, but EVERY time she goes in a pool she poops. Never fails. Lemme tell ya...that's when a hose comes in handy, especially with those built-in swimsuits w/ really wet poop inside....ewww.
I have a reusable/washable swim diaper, but I don't know where it is. The gym we go to sells them b/c kids under three are required to wear a swim diaper.
Re: How do you take a diapered child swimming?