In the swim in Hawaii

For maximum speed,” the kid tells us, “ride lying down like this.” He folds arms over chest, Egyptian mummy–style.

Standing in swim trunks and sunscreen, my son and I pay close attention. With waterslides, experience counts. And this kid has already let us know he’s gone down Lava Slide 48 times in the past two days.

As for us, it’s our first time on Lava, the longest waterslide at Maui’s Grand Wailea Resort Hotel & Spa’s Wailea Canyon Activity Pool, acclaimed by cognoscenti to be the most elaborate resort swimming pool in the world. (And you pay for it, with hotel rooms starting at $575 per night.) “There’s a phenomenon in Hawaii,” says Matthew Hart, the resort’s former general manager, bemusedly. “People would rather go to the pool than the beach. It’s a mystery.”

But does the Pacific Ocean ― which is, admittedly, just a few yards away ― have Wailea Canyon’s faux volcanic grandeur, not to mention nine pools, seven waterslides, six waterfalls, the swim-up Grotto Bar, the Tarzan Rope Swing, and the world’s only Water Elevator, totaling up to 770,000 gallons of fun? For someone in the right demographic ― say, a 10-year-old, just the age my son happens to be ― Wailea Canyon is aquatic paradise.

And so we’re there the minute the pool opens, obtaining our ID bracelets and our Wailea Canyon map, the pool being complicated enough that you need a map. Then we’re off, following Mr. Expert down Lava Slide and clambering up fake rock mountainsides to the Ana Puka Slide, and plunging through the Rapids Slide, which duplicates falling off a raft at Lava Falls on the Colorado River or maybe putting yourself through the spin cycle in your Maytag. Finally I bob behind my son on the lazy river, wondering if any of the nice people gazing down at us from their lounge chairs can perform CPR.

“I don’t think there’s another pool like this,” says recreation supervisor Josephine Kamaka-Keliiliki. She helps oversee Wailea Canyon operations, directing a staff of 50, the most visible of whom are the associates who perch at key poolside points to make sure everybody is playing safely. With suntans and cell phones, the associates radiate a Neptune-like authority. “It’s so cute,” Kamaka-Keliiliki says. “The little kids follow the associates around. The older kids want to get the associates wet.”

And vice versa. At the Tarzan Rope Swing, it’s the associate who’s wielding the water gun, quizzing kids as they swing out over the turquoise water.

“What’s the name of SpongeBob SquarePants’s pet?” he barks at a little girl.

“Patrick,” she tries.

“Wrong! Gary the snail!” He squirts her. 

Then it’s time for the Water Elevator ― the world’s only one, the Grand Wailea’s promotional literature takes great pains to say. We wait, treading water, until an associate creaks open a large metal door in an artificial cliff. In we swim. The door closes, and water pours into the now-sealed chamber. At this point I expect to hear the disembodied voice of Dr. Evil: “Not going to talk? Perhaps a little ride in the Water Elevator will loosen your tongue.” But before the water goes over our heads, we’re borne upward with the other passengers and deposited near the top of Lava Slide.

Mr. Expert is there, presumably on his 79th ride. But we don’t need him. The map is shredded and soaked in my bathing-suit pocket, but we don’t need it either. We’re the pool experts now.

On the slick swirl downward, it dawns on me why places like Wailea Canyon work. On some days, it seems that 90 percent of your job as a parent is saying no. Here, 90 percent of the time, you can say yes. Yes, you can go in the Water Elevator; yes, you can squirt the associate; yes, you can make me jump off the Tarzan Rope Swing too.

It is a nice insight, but it doesn’t last ― we’re in the rapids, and I’m upside down, my head bumping into somebody I don’t know. I hear my son laughing. It is getting late: We need to pack, check out, and head to the airport and home. But first we have to do Lava one more time, and the swing, and Ana Puka again, again, again, again.

INFO: The pool is open only to guests of the Grand Wailea Resort Hotel & Spa in Wailea, Maui (rooms from $575; 800/888-6100).