Here's my summer swim team, the Glenwood Tigers, from many moons ago. I'm pretty sure I'm the fourth from the right in the front row with the white jacket and the headband.
I was an okay swimmer--not a star by any stretch of the imagination. But I worked hard, learned the strokes, and had fun with my summer friends. Since I went to Catholic school, I didn't see most of these kids during the year. Actually, I'm not sure how many of them saw each other, since I think the pool probably drew from more than one public elementary school neighborhood.
I think one of the greatest things about summer swimming is--assuming the parents and kids don't go all competitive crazy--that it builds community. What other activity brings together boys and girls from ages 3 or 4 (if we include pre-teamers) up to age 18 or 19 as well as parents and often college-aged coaches year after year after year?