A friend of mine... from the time his son was barely 2 years old.... (they have a pool), taught him how to be in the water, float, swim, not be afraid of the water etc. He taught his son, on his own, not with formal lessons.
Bear in mind, this is Hawaii... and my friend, is a total Watersports man.
His son is now 6 years old... AND surfs with his Dad. He can, surf by himself on his own surf board... and swim very, proficiently. And does kayaking... 2-man style. With his Dad.
My friend, taught his son all this, for 'safety.' From when he was a toddler.
Me... my sister taught me how to swim.... just naturally while at the beach with family. As do many kids, in Hawaii. My parents never taught me per say... but I vividly remember my older "bossy" sister, teaching me.
We had a pool, growing up. No one, when I was a child... went to any 'formal' swim lessons, at all.
all the best,
Susan