At 9:30 on Tuesday morning, about 20 children eagerly gather poolside at Summit Chase. Just weeks ago, confined to schools and preschools, they could only dream of spending the morning freely splashing in this blue-green water.

Now, as instructors give the word, some enthusiastically launch themselves feet first. Others ease in, cringing as the water creeps up their goose-bumped legs. It's immersion in a summer ritual that is also a rite of passage: swimming lessons.

Vino Wong/AJC (ENLARGE)

Jackson McNew, 5, dips under the water while learning how to swim at the Summit Chase Country Club swimming pool in Snellville on Tuesday. His mother, Rebecca McNew of Monroe, is just one of the many mothers and grandmothers in attendance supporting the young swimmers.

Vino Wong/AJC (ENLARGE)

Jackson McNew, 5, takes a leap into the pool under the watchful eye of swim instructor Andrea Orton, 18, (right) as Lily Claire Hewatt, 4, and Anderson Pitts, 4, both of Loganville, watch.

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These young swimmers have been brought here by mothers and grandmothers carrying tote bags stashed with towels and sunscreen for the first of five rounds of classes that will take place on this day. By the end of the 6 p.m. session, about 100 kids will have stroked and kicked their way to improved water skills at this private club, nestled in a Snellville neighborhood of neat two-story houses.

This morning ritual is repeated at dozens of pools across metro Atlanta. Learning to swim can be just for fun or the gateway to a competitive sport for kids of all ages.

In Gwinnett County alone, more than 6,000 swimmers are part of 46 teams, giving the county claim to one of the country's largest recreational leagues. The Summit Chase Sharks have participated in the league for 25 years.

As Tuesday's lessons begin in each of the pool's six lanes, the water in the shallow end feels lukewarm to the hand, but Jackson McNew complains.

"This water's freezing," says Jackson, who says he'll be 6 in August. He plans to invite all his school friends — boys and girls — to Chuck E. Cheese for a party.

"My turn. My turn. My turn," yells Anderson Pitts, who's 4 going on 5.

"It's Lily's turn," says instructor Andrea Orton, 18. "Lily, you've got to start using your arms."

Lily Claire Hewatt, 4, cups her hands and does as she's told.

"Good job!" exclaims Orton.

Similar compliments ring out from other instructors in other lanes. "Good, Sarah, good!" "Good work!" "Good, good, good!"

"My turn, my turn, my turn," says Anderson as Lily finishes her swim.

Anvi Shetty, at 3 the youngest of the four swim classmates in Orton's lane, swings from the handrail on the pool steps, echoing Anderson. "My turn now. It's my turn," she singsongs.

One by one, the four little swimmers kick their way down half the length of the pool and return, first on their backs, then on their stomachs.

"Put your face in the water," Orton instructs Anvi.

"Use your arms in big circles," she advises Jackson.

"I can remember being little like them and not knowing anything," Orton says later. "It's cool to see them for the first time and then watch them later in swim meets and know you've taught them."

At the end of the lesson, Orton's four students line up on the edge of the pool to jump in and swim to the steps. Jackson adds his own sound effects.

"Pow, pow, pow!" he yells as he hits the water.

"Good job!" exclaims Orton.

"My turn, my turn," says Anderson. "I'm after Jackson."

He jumps in and makes his way to the steps.

"Good job!" says Orton as Anderson climbs out. "You're all done."

The two boys walk-run across the pavement toward their mothers, squinting as water runs down their faces.

When he's been towel-dried, Jackson describes his accomplishments: "We jumped. I swam halfway back to the wall, got up, breathed and swam the rest of the way to the wall. It was hard."

Anderson is looking to the future and to the row of low white diving boards extending over the deep end.

"Maybe when I'm 10," he says, "I'll jump off one of those."