When can I bring my baby swimming?

When can I bring my son swimming?! He's just turned three months and I'm dying to see what his face is like in the water!! But I don't know if I need to wait till he has all his injections?! And will the water be too cold for him? I looked up baby classes online but none seem to say what age they can start and also they're incredibly expensive to do!? Anyone bring their baby swimming at three months? Also anyone do the water babies classes with their baby and was it beneficial?! Thanks :)