One of our pleasures is swimming every week we go to a swimming class specifically for babies. There aim is to teach babies to respect water and they take advantage of the mammalian diving reflex. Nate loves the water, I suppose being a water birth helps this. Its great seeing how swimming socialises the babies as well, they have to wait their turn and watch the others while waiting. We started swimming at 9 weeks and I think it was probably the best time to start for us.