i took my lo swimming at about 4 months, but he didnt really do a whole lot until he got closer to a year old, and he was very tired and very hungry and very cranky as soon as we got out of the pool. He did seem to enjoy his time in there though... kicking and splashing as best he could. Can't keep him out of the water now though, so i guess that is one benefit to getting them used to the idea early.
Kristina
BC Canada