(CNN)Veteran scuba divers avoid dry land, even when they sleep.
They bunk on cushy yachts, known as liveaboard dive boats, anchored over the ocean's most stunning coral reefs.
Because liveaboards cover both bases: They're dive boats and floating hotels.
These aren't massive cruise ship cities.
They're more like private yachts, ranging from 100 to 200 feet and hosting 10 to 20 serious divers.
Solo divers can bond with new friends, or groups can book the whole boat and have a influence over the itinerary.
Either way, the diving is easy.
Just plop off of the dive platform -- day or night -- and the reef is right below, stunning and breathtaking.
After the dive, chilled fruit and cocktails are waiting, along with a freshwater hot shower and warm towel.
Here are five of the best:
The Arenui (Indonesia)
Indonesia's traditional wood-built boats are called "phinisi" and have a Captain Jack Sparrow, pirate-ship feel to them.
Besides a stock of rum and lots of hardwood, the similarities end there and the service begins.
The 140-foot Arenui is custom-built with 12 different types of woods (the owners say 70% is recycled) and has intricate wall carvings depicting Hindu legends.
Eight deluxe cabins house just 16 passengers attended to by a crew of 22.
When they're not serving gourmet cuisine, they're setting up massages and spa treatments on the sundeck or talking about the next dive or land tour.
What to see
The Indonesian archipelago is part of the Coral Triangle, which encompasses Malaysia, Papua New Guinea, the Philippines, East Timor and the Solomon Islands and is home to some 500 reef-building coral species.
By comparison, the Caribbean has only 70.
The massive stands of hard corals are impressive, but the mind-blowing multicolored soft corals in purple, yellow and magenta are reminders that underwater Indonesia is another universe altogether.
It's home to mantas and sharks, dramatic lionfish, frogfish and clownfish, and a host of psychedelic snail-like nudibranchs.
The primary dive areas are Komodo (yes, home to the famous land-based dragon), Raja Ampat, Ambon, the Spice Islands of Maluku, Banda, Alor and Flores.
The trips cover a lot of territory -- hundreds of nautical miles -- in seven-to-13-day itineraries.
Expeditions visit volcanic regions and one dive in Komodo is in the shadow of an underwater volcano.
At Alor, there's also drama above water where a volcano erupts every 30 minutes.
The Arenui, Bali, Indonesia; +62 361 750034
The Dewi-Nusantara (Indonesia)
This ship has what is perhaps the largest private cabin (500 square feet/46 square meters) in the liveaboard family.
Covering the full width of the vessel, the master suite has 180-degree views of the ocean and furniture created specifically for the boat by French artist/interior designer Bruno Helgen.
Even the bathroom has an ocean view.
The ship is one of the largest liveaboards on the market at 190 feet (58 meters) yet it still books only 18 guests.
A three-masted schooner, she really does look fresh off the set of "Pirates of the Caribbean," even though she's full-blooded Asian Pacific.
What to see
Itineraries are a minimum of 11 days and tour many of the same locales as the Arenui, but the ship also hits Cenderawasih, a remote reef area that's been called the Galapagos of Indonesia.
The jewel of Cenderawasih is the gentle whale shark that frequents these waters.
Cetacean sightings of spinner dolphins, orcas and various whale species, including melonhead, pilot, blue and humpback whales are common.
A trip on the Dewi Nusantara -- translation: Goddess of the Archipelago -- is like sailing on a masterpiece.
But guests shouldn't be afraid to throw their feet onto a table, where, if they're not careful, a crew member may begin massaging their toes.
The Dewi-Nusantara, Indonesia
The Red Sea Aggressor (The Egyptian Red Sea)
The Red Sea Aggressor is one of 18 Aggressor boats scattered around the planet with two more coming online soon.
Aggressor is by far the largest franchise in liveaboards and guests know what to expect, like a Hilton or, in this case, the Ritz.
The Red Sea, a spacious 120-foot yacht with a 26-foot beam, hosts 20 guests and is built for comfort.
Each cabin has a flat-screen TV with a selection of 400 movies and TV shows.
There are three master staterooms, and seven deluxe staterooms -- all with en suite heads and fingertip AC controls.
Like all Aggressors, one of this boat's favorite hangouts is the massive sun deck with shading, chaises lounges and deck chairs, a bar and, of course, the ever-popular 24/7 Jacuzzi.
What to see
Rumor has it that Jacques Cousteau claimed the Red Sea was his favorite place to dive.
The visibility is some of the best in the world and there are abundant stands of soft corals, as well as more than 1,000 species of fish.
Sharks and dolphins are seen frequently.
Turtles, rays, eels, massive schools of fish and even the occasional dugong pass by.
Overall, the diving has such a wide variety of corals, pelagics, caves, walls and wrecks that it's easy to agree with Captain Cousteau.
In true Aggressor style, they've thought of everything from the best airport to fly into in Egypt (all flights go through Hurghada) to booking extended land-based trips to Cairo and Luxor.
The ship sails from Port Ghalib, a friendly waterfront community with lots of shopping and local eateries.
The Red Sea Aggressor; +1 706 993 2531
The Argo (Cocos Island, Costa Rica)
Argo is the ship of choice for anyone wanting to dive to 1,000 feet.
It's the only liveaboard with its own submarine, aptly named the DeepSee.
This state of the art submersible is parked on the stern deck, ready to take two passengers and a pilot as deep as 1,500 feet (450 meters) where numerous new species have been discovered.
A four-inch-thick acrylic viewing sphere gives passengers a 360-degree view.
Built as both a luxury liveaboard and a working yacht for research expeditions, the Argo spends time in Costa Rica but is sometimes chartered by outfits like National Geographic for research expeditions to Galapagos and other distant island chains.
The Argo itself is as stable as a tank and at 130 feet (40 meters), she carries 16 guests in eight spacious cabins with shark art painted directly on the walls.
What to see
Here's a hint: The 1999 documentary "Island of the Sharks" was filmed here.
Schooling hammerheads, white-tipped reef sharks, tiger sharks, Galapagos sharks, whale sharks -- they all thrive in Cocos Islands' natural environment.
In other words, this is not a bait-induced shark dive like those found in many tourist locations.
These gray suits are on site and on the move all the time.
This land of giants is also home to mantas, spotted eagle rays, dolphins and whale sharks, as well as reef-dwelling species such as lobsters, eels and their slimy brethren.
Cocos is as high-action as diving gets and many hardcore divers proclaim it as the best big-animal diving in the world, going back year after year for their adrenaline fix.
Hundreds of waterfalls spew off the dense green island and for centuries whaling ships used Cocos to replenish their water supplies.
Guests can go ashore and get the full force of a waterfall shower and also see names carved in the rocks by ancient mariners who visited the island.
The Argo, Costa Rica; +506 2228 6613
Carpe Vita Explorer (Maldives)
Perhaps the most unique aspect of the 125-foot Carpe Vita is its 60-foot dive tender called a dhoni.
It keeps divers dry and comfy going to and from the mothership to dive sites.
Many liveaboards have support boats to access sites with tricky anchorages, but this one ups the game with a full bath and hot shower.
It also houses all of the dive gear and compressor systems.
That way, the Carpe Vita can focus on cushy lounges, hot tubs and large cabins.
The ship has two VIP suites on the upper deck with showers and a full-size bathtub, a rare find on liveaboards.
The ship carries a maximum of 20 and offers both seven-day and 10-day itineraries depending on the season.
What to see
In addition to postcard-perfect beaches, there's one thing guaranteed in the Maldives: manta rays.
During the May-to-October monsoon season, the massive rays descend in huge numbers.
Divers who are calm and patient will get a show that sometimes lasts half an hour or more.
In general, diving here is divided into three distinctive experiences: inside the atolls, outside the atolls and riding strong currents through coral passes to mingle with huge congregations of fish.
Familiar species like grouper and snapper are everywhere along with a favorite headliner, the bizarre but friendly giant Napoleon wrasse.
Depending on who's counting, the Maldives has more than 1,000 palm-fringed islands and a couple of dozen coral atolls scattered across 500 miles of equatorial Indian Ocean south of Sri Lanka.
Cameras can be pointed almost anywhere to snap the quintessential white-beach, turquoise-water photo -- perfect for Instagram or Snapchat.
Carpe Vita; +1 307 235 0683