When it’s my turn, I follow the fins and bubbles of the diver ahead of me, into a tiny dark spot in the reef wall.

This time through the tunnel in the reef, I’m much more comfortable, both with being under the water and with being in the caves. My breathing is more even and regular, although I’m still having a little trouble with my tendency to float. (Louis will tell me later that more yoga will help control my breathing and my positive buoyancy.)

We continue on, swimming through an amazing sunken mansion, through dark "hallways" in the reef to open "rooms." Some of the passages are narrow, closed overhead. Others have openings to the surface where shafts of sunlight spotlight the columns of bubbles as each diver passes through.

In every room—some bigger, some smaller, some closer to the surface, some deeper—Louis counts heads and checks our air supply. Despite some rapid breathing, everybody’s air supply is good.

In what seems a very short time, long before I’m ready, we pop through an opening and find ourselves the ante-chamber inside the "front door." We scoot out into the light and pop to the surface.

Grinning silly grins around our mouthpieces and masks we all add a little air in our buoyancy compensators (BCs in SCUBA parlance) so we can float despite the weight of our tanks and gear. Masks off, mouthpieces out, and now we’re all grinning and smiling for real. High fives for each other and handshakes thanks for Louis.

I’ve gotten my first taste of las cuevas submarinas. Now I’m a glutton—I want more. I see the photo possibilities La Cueva Submarina dive shop owner "Pain" (pronounced pa-EEN) Acivedo talks about so much. I will be back.

I still have five more routes through las cuevas to explore.

*NOTE: the SCUBA Adventure package does NOT make one a certified diver. La Cueva Submarina offers classes for those who wish to become fully certified SCUBA divers.

Our guide, Louis, stops at the end of this shallow reef canyon. He points to an even darker spot in the reef. "Through there," his gesture says.

"Through there?!?!" I think. Louis points again.

The first diver goes through, disappearing into the darkness of the reef. Then the second goes through. The third diver in line, a tall very thin woman, balks and shies away. Louis gently takes her hand and pulls her to the opening. He goes through ahead of her, then turns to take her hand again, guiding her though the hole.

Then it’s my turn. A slight hesitation. What if my regulator catches? Or my air hose tears? (Too many years watching Sea Hunt and James Bond movies.) What if the opening isn’t big enough? What if…

I take a deep breath—and then remember not to hold it—and plunge down into the darkness.

I’ve just gone through the front door to Las Cuevas Submarinas—the Underwater Caves. This is one of the most popular dive sites on the northwest coast of Puerto Rico. Divers come from all over to dive this series of caves.

The first stop on the way to the Underwater Cave is the dive shop La Cueva Submarina. Located right at the top of the hill on Carr. 466 above Playa Jobos, La Cueva Submarina organizes these tours into the caves. For $55 even someone with little or no diving experience can get a taste of these amazing living formations. Called the SCUBA Adventure package, the price includes introductory training, all the equipment and guides.* This is the first and easiest of the six routes charted through the caves. The deepest we go on this dive is about 35 feet.

On the other side of the first opening is a small, surprisingly bright, almost-spherical cave in the reef. We all congregate there waiting for Louis to lead us on the next leg even though it’s obvious there’s only one place to go – down through the next opening. We can see it, a lighter ragged tear in the reef. Once all of us are accounted for in the entrance cave, Louis dives through to the light beyond. Please see La Cueva Submarina Part 2 to complete the dive.