I have no idea why I spent the better part of two decades terrified to swim in deep or dark water; I practically grew up on sailboats, always within reach of a lake or the ocean; there are pictures of me as a little girl, happily floating in deep, sometimes dark, open water; but at some point since then, for some reason, I got scared.

My lack of an explanation occurs to me as my boyfriend and I book our trip to one of the scariest places on earth that I can possibly choose to confront my fear.

The Great Barrier Reef, off the north east coast of Australia, is the world’s largest coral reef system. At some 1,600 miles long it’s clearly visible from outer space. It’s also one of the most complex, stunning and endangered ecosystems in existence. Untold thousands of tourists snorkel and dive here every year, and for most people it’s a once in a lifetime experience. I know I will live with regret if I don’t join their ranks.

And that’s not living.

I think to myself, Carpe diem! We make the reservation…

To my astonishment I’m not nervous when the morning of our trip arrives.

This is impossible! Where is the paralysis, the dry mouth, the closed throat, the shaking body?!

We step aboard.

Nope, still not scared.

The boat pulls out of the harbor and as we cruise toward the reef we sit through an introductory diving lesson. This seems more like a tutorial on the many terrible things that can happen when one goes underwater in the southern Pacific. Yes, there are sharks in the vicinity… If you hold your breath while diving you could die, and so on.

Okay, maybe I’m a little nervous now, but still not afraid.

As we sign the requisite waivers, the boat stops, we drop anchor and the captain turns off the engine.

Aha! There’s a lump in my throat! What’s that?!

We decide to hold off on SCUBA diving until after we live through a round of snorkeling. My throat closes tighter as we squish into our fins and masks, but still, this is not the sheer terror I was expecting. The other swimmers are jumping in. There are toddlers out there, and elderly couples…

I can do this.

Finally I’m standing on the swim platform trying not to look down at the reef and the fish waiting below, and it hits me that this is the first time I’ve ever confronted a physical fear. I’m overcome with emotion and I swallow hard to stop tears. There’s nothing left to do but jump, and suddenly… I’m in.

My boyfriend takes my hand and the next thing I know we’re swimming, a rainbow of fish everywhere, the warm current carrying us away, and I completely lose track of time. The underwater world is profoundly peaceful, and almost magical. Pretty soon I’m off on my own, holding my breath to dive deep and pose for pictures. This is liberating! I feel invincible!

Over here! Look at this!

One minute I’m swimming through a school of bright purple fish, thousands of them! The next, I’m playing hide and seek with some clownfish.

Less than an hour later we’re 60 feet down in the deep, dark southern Pacific, in full SCUBA gear, and I’m marveling at a sea cucumber in the palm of my hand. Thoughts of my old fear occasionally drift by and keep going, as if they belong to someone else. And in a way, they do.

Back on the boat deck, I peel off my wetsuit like a superhero taking off her cape after saving the day. It’s all over, almost as soon as it started! I am amazed, fully realizing what I’ve just done. This was supposed to be so much harder! For all those years I stayed on shore, or in the boat, holding back, missing out, and this was so easy.

Yes, I had someone I love with me this time, and I felt safe with him.

But I’ve felt safe many times before and still not jumped in. What else is different?!

As I stand there dripping, I decide to be proud of my accomplishment, rather than analyze it. What matters right now is that I did this. Maybe the understanding comes later. Maybe there is no moral-of-the-story. Maybe we’re just ready when we’re ready.

The crew pulls up anchor and soon we’re steaming back to shore. The sun warms my tired body as I watch dolphins jump and play in our wake. The shadowy reef shrinks from view. Stormy skies roll in behind us and rain begins to wash away our traces. A waterspout forms from the clouds just far enough away so that we can watch it in awe instead of angst.

This place is still wild despite relentless human invasion. If I can conquer my biggest fear here, I can’t wait to find out what comes next.

SHANNON MULLEN is a freelance public radio reporter, amateur chef, aspiring screenwriter and a fantastic aunt. She's based in New England, where she spends a lot of her free time taking long walks/runs, hiking and otherwise exploring with her black lab Mila. Click here for more of Shannon's outdoor fitness adventures and visit her blog People, Places & Things »

Related Chi: Climbing Problems