Forty-five feet underwater, gliding above reef strewn with the eerie wreckage of a World War II cargo ship, we can easily see what Hurricane Irma has done to Florida Keys near Key Largo.

And it is spectacular.

A green sea turtle swims amid the coral reef tract near John Pennekamp Coral Reef State Park in Key Largo, Fla.
Florida Keys News Bureau
A green sea turtle swims amid the coral reef tract near John Pennekamp Coral Reef State Park in Key Largo, Fla.

Sea life is in abundance: angelfish, yellow jack, and ungainly trumpetfish, all in iridescent shades of neon blue and taxi yellow; silvery shimmering grunts and red snappers by the thousands; an enormous turtle whose barnacled shell is the size of a child's wading.

The storm last September heaved sand up from the sea floor, dashed it against the reefs, and scoured away harmful algae, enhancing the environment for the diverse sea life. It also uncovered artifacts (such as a decades-buried anchor) and opened up new swim-though passages in arches of coral.

North America has only one living coral barrier reef, the third-largest such system in the world, running  220 miles from Key Biscayne to the Dry Tortugas. Government conservation efforts came late to these reefs. It wasn't until 1963 that America's first underwater national park was established with the opening of the 80-square-mile John Pennekamp Coral Reef State Park, which put Key Largo — about two hours south of Miami down U.S. Route 1 —   at the epicenter of American reef conservation.

Although there is still some ongoing cleanup from Hurricane Irma, Key Largo got off easy. And for all of the destruction Irma caused on land, these storms often do much to benefit a reef, rearranging the underwater topography and making familiar dive sites new again.

We chose Key Largo because we wanted a dive trip of near-Caribbean quality at a less-than-Caribbean cost. When I polled my friends who dive, Key Largo came up repeatedly, even among those partial to exotic overseas locations.

Key Largo is a tourist town, and lodging isn't cheap.  For its  "old Florida" charm, we chose the Bay Harbor Lodge, a collection of small, scattered structures. The history is a bit obscure, said owner Peg Laron, but it was partly built in the early 1950s, most likely as a fishing camp.

Tucked back on a meandering driveway lined with gnarled gumbo-limbo trees and an elaborate garden, the lodge has grottoes with seating and a small private beach with kayaks for guests. Our room was snug, with its own kitchen, tile floors, and patio where we could dry our dive gear. (That "old Florida" charm included a hint of tropical decay, with some peeling paint in the bathroom along the baseboard of the clothes closet. Yes, the closet was in the bathroom.) The on-site food truck provided coffee and fresh scones each morning. The mango scones were just right, with succulent chunks of mango.

Christ of the Abyss is perhaps the most photographed underwater site in the Florida Keys.
Sebastian Carlosena / panoramio.com
Christ of the Abyss is perhaps the most photographed underwater site in the Florida Keys.

Most diving operators offer two trips a day, each trip visiting two dive locations. "Cattle boats" carry 15 to 50 divers at a time; if you seek underwater tranquility, you won't enjoy 49 finned friends churning up the reef around you. So we looked for outfits that limit the number of divers to six or so. These boats will often go out with as few as two divers (or four snorkelers) at about the same cost as the larger operations. The top recommendations were Island Ventures, which was sold-out during our trip, and Quiescence Diving Services, which   had immediate openings. (Trips start at $90 each, including tanks and weights.)

We boarded one of Quiescence's three Delta Puma 25 diesel dive boats, a spartan vessel captained by Tim Shaw, who took five of us to the Christ of the Abyss. Perhaps the most photographed underwater site in the Keys, it is an 8½-foot-tall bronze statue of Jesus in 25 feet of water. Shaw gave a thorough pre-dive briefing including reef navigation, safety procedures, and a dryly comical and detailed history of the statue.

The next day, with Dave Montgomery at the helm, we asked to go to the wreck of the SS Benwood, a World War II cargo ship that went down in 1942. It was running without lights to avoid U-boats when it collided with another blacked-out ship. The Benwood sank in 45 feet of water and now serves as an artificial reef. Many dive operators keep a set schedule — sorry, Friday is Benwood day, not today — but after a show of hands, off to the Benwood we went.

If you want to add a little eco to your tourism, you can volunteer with the Coral Restoration Foundation. With a half-day's training, you can do two dives to help maintain, grow, or plant new reefs. There is a CRF fee or $30 to $65, and you'll pay full fare for the dive. (If you are an experienced diver with the right certifications and have three weeks to dedicate to volunteering, your dives are gratis.)

As a novice diver, my most critical lesson was on seasickness. Experienced divers said to take precautionary Dramamine an hour before getting on a boat, per the instructions. It did not work. The boat captains said about 60 percent of divers get ill, and the trick is to take it at least a day before.

Jim Chimiak, medical director for dive safety organization at the Divers Alert Network, agreed. "One dose mightn't get you to therapeutic level," he said. In fact, he said to try a seasickness medicine before your trip. "If you are taking medication for the first time, see how it affects you in a benign environment," he said. "Take it and walk around the house."

The area offers lots of inland activities. To name just three: The Dagny Johnson Key Largo Hammock Botanical State Park has six miles of hiking trails; the Florida Keys Overseas Heritage Trail offers 90 miles of trail for walking, running or cycling; and you can see more than 100 types of birds at the Laura Quinn Wild Bird Sanctuary.

But the central attraction has been, and still is, the reef.

Bay Harbor & Coconut Bay Resort: 305-852-5695 or bayharborkeylargo.com. (Rooms from $185.)

Quiescence Diving Services: 305-451-2440 or keylargodiving.com.

Island Ventures: 305-451-4957 or islandventure.com

Dagny Johnson Key Largo Hammock Botanical State Park: 305-451-1202 or floridastateparks.org/park/Key-Largo-Hammock. (Home to many protected plants and animals, this park has many wheelchair-accessible trails. Entry: $2.50.)

Florida Keys Overseas Heritage Trail: 305-853-3571 or floridastateparks.org/trail/Florida-Keys. (The longest contiguous paved segment of this 90-mile hiking and biking trail runs 34 miles from Key Largo to Islamorada. Free.)

Laura Quinn Wild Bird Sanctuary:  305-852-4486 or wildbirdsanctuary.com. (Hundreds of birds and permanent guests like great horned owls Samson and Delilah. Free.)

John Pennekamp Coral Reef State Park: 305-451-6300 or pennekamppark.com. (The first undersea park in the United States. Camping, fishing, swimming, and picnic areas; 30,000-gallon saltwater aquarium; snorkeling, scuba, and glass-bottom boat tours. Adult snorkeling tours from $29.95; scuba tours from $75; glass-bottom boat tours from $24.)