All children should learn to swim. The age at which they should take their first lessons is still a little controversial though.
While the American Academy of Pediatrics is no longer against swim lessons for toddlers and younger preschoolers, they don't actually recommend that all kids start that young. Instead, because early swimming lessons may help lower a child's risk of drowning, they say that parents might want to think about enrolling their kids in a survival swimming skills class if they think the benefits outweigh the risks.
They still stress that early swimming lessons won't drown-proof your child. In fact, nothing ever will. That's why a layers of protection plan, with multiple safety barriers in place, like an isolation fence around the pool, adult supervision, and making sure kids always wear a Coast Guard approved personal floatation device, etc., are important too.
Although many experts still don't believe that research supports all kids taking early swimming lessons, learning survival swimming skills might be a good idea to make up the very last layer of your protection plan.