The Wetter The Better

Since I'm not a great swimmer I'm no great snorkeler, so I spent a lot of time in the shade of the scraggly beachfront trees, nursing minor coral burns and an iced Scotch. But our teenage boys spent hours out there just below the surface of the Caribbean. One afternoon Jordan showed off a starfish, an orange crab and a sea snail and returned them to their rightful places without incident.

On other vacations, snorkeling was a planned excursion -- you made reservations, hired transportation, plopped in the water, enjoyed yourself, then returned home. Sapphire Beach was more like a drop-in, all-you-can-snorkel buffet, serving fresh sea life whenever you're in the mood. Once I went out to the reefs when it was nearly dark, just because I could. I didn't see much, but that wasn't the point.

Walk This Way

Our best subterranean adventure came on a reef walk called Sea Trek, where we were escorted along a nature trail about 20 feet below the surface. It's located at the Coral World Ocean Park, a sort of shabby U.S.V.I. version of Sea World.

The underwater stroll is possible thanks to a large white Buzz Lightyear helmet that sits on your shoulders. Like a cup held mouth-down underwater, the helmet holds a cavity full of air. An oxygen hose running from a pump on the surface to the rear of your helmet provides pressurized fresh air that eventually escapes via small holes in the back.

This takes a few minutes to get used to, standing seven meters below the surface, your head surrounded by a bubble of oxygen, wearing just a swimsuit, gloves and underwater booties. Your breath sounds like the guy in "2001" when he's trying to disarm HAL.

But just like the guides topside promised, you can breathe just fine in that get-up, and even when you tilt your head the water doesn't rush in. Once you quit worrying, Sea Trek may be the best way to experience the Caribbean that doesn't require certification or a propeller. My son and I spent nearly half an hour loping like bare-chested astronauts along the path, which is lined by a fat metal chain. The eye-level reefs display the usual assortment of tiny speedy fish, exotic fan corals, and various organic attachments like anenomes and little olive-colored pennants that drift in the currents. We saw a trumpetfish, an eight-inch, eel-like thing that shimmies at a 45-degree angle, two yards away. Elsewhere we'd seen trumpetfish recoil fiercely into a slingshot and strike prey, but here it gave us no alarm.

When a sea spider drifted by, a guide "captured" it by surrounding it with his hands and pushing it toward us. Imagine a subaquatic daddy longlegs the size of a ball of yarn, elegantly arching its articulated limbs through the water in slow motion, coming to rest in your hand.

St. Thomas offers many ways to explore the sea, such as walking the underwater coral trail at Coral World Ocean Park.( - Coral World Ocean Park)

Now imagine not freaking out while it sits there. That's the kind of peaceful immersion Sea Trek produces. I began to understand how divers could spot "harmless" sharks 20 feet away and not thrash madly to the surface: When you're in the midst of all that bounty, you feel like just another denizen of the deep, but one big enough to be of no interest to feeding creatures. I was glad one of those massive groupers didn't happen by, though.

After the sea spider and the trumpetfish, holding a rust-colored sea urchin on my bare palm seemed natural, even when its hundreds of tiny fingers attached themselves to my skin. When the guide gently pulled it off, the creature yielded like reluctant Velcro.

We reacted pretty much the same way when it was time to return to our lives at the surface.