Mention barrier reef to most gringos and Australia, not Belize, will come to mind. While divers can certainly make the half-a-world trek to descend Down Under, the second largest reef in the world (185 miles long) is fortunately only two hours from Texas—which means, if you time it right, you can be swimming with the fish the same day you left your house. That is, unless you forget your diver's certification card, which is something I discover I have done just as I reach the counter of Reef Adventures, one of the island's 30-plus dive outfitters. This is not surprising, considering my relaxed state of mind. Down the pier my friends are already gearing up; I'm bringing up the rear after a far-too-filling lunch of conch fritters, snapper, and coconut rice at Cannibal's Beach Bar.

That's precisely the problem with Ambergris—if you could even call it a problem: As good as the scuba is, this island is probably the only place in the world where getting things together for diving is almost a drag—why trade lazy, sunny pleasure even for deep watery treasure? The weather is perfect, and has been since I arrived: 85 degrees and sunny. I have yet to see a cloud in this country; it's my second diving trip to Belize in three months. My friend Rob, through means the rest of us have yet to determine, has managed to procure a house on Ambergris. And more phenomenally, he lets his friends use it at will.

Fortunately, dive master Ched Cabral is willing to overlook my missing card and let me go. I suppose he trusts that I am a total pro (or a complete geek), shouldering my new BCD and dive computer; all-matching pink fins, snorkel, and mask; and a wetsuit completely unnecessary for the 86-degree water.