This is only my third dive and it got off to a shaky start when my weight belt fell off on a backward roll entry. He tucks my arm through his and together we explore the large patch reef with its whimsical, mushroom-shaped corals. He points out reef sharks, sea fans, clown fish, vivid crinoids and intricate sea sponges in bright shades of yellow, orange and red before we surface in thousands of Champagne-like bubbles.
Back on board, Cousteau's kindly face is beaming while the L'Aventure Jean-Michel Cousteau dive team are on a high: thrilled at having dived with their boss and underwater idol.
A couple from the US Midwest are shaking their heads in disbelief that they too got to dive with the son of the man known as the "King of the Sea". They ask Jean-Michel to sign their diver's logbook and the relaxed 73-year-old happily poses for photographs.
Given that his father pushed him and his younger brother Philippe overboard with tiny aqualungs strapped to their backs in the Mediterranean Sea aged seven and five, it should come as no surprise that Jean-Michel is so comfortable in the water.
Most children would have been daunted, but Jean-Michel, nursing a glass of French Côtes du Rhône at dinner that night, says it was a defining moment. From that time on his life has emulated his famous father's: exploring the depths of the oceans and imploring the world to take care of them.
Nevertheless, carving out a path for himself was not necessarily easy. It's widely known that his brother Philippe was the favoured son, the one chosen to take over the Cousteau legacy and empire. There were other family issues, too. His father secretly had a second family with Francine, whom he married after Jean-Michel's mother Simone passed away.
Despite this, and the fact Jacques took legal action to try to stop him using the Cousteau name for the resort he founded 25 years ago, Jean-Michel's devotion and admiration of his late father is absolute.
He also speaks lovingly of his brother who tragically died in a seaplane accident in 1979.
If there are old wounds, Jean-Michel handles them with dignity and doesn't dwell on the past.
"My father was so curious and always wanted to go where nobody had gone. His focus was always on 'what do I need to go there?' Jacques invented the diving regulator, the precursor to scuba diving, which made breathing underwater accessible to everyone.
"Later, he created the first non-military submersible and structures where people could actually live underwater.
"If the tools didn't exist he invented them," Jean-Michel said.
Jean-Michel has never wavered in taking up his father's fight to preserve and protect the oceans. He is a well-known marine biologist in his own right and qualified marine architect; he has made countless films and documentaries and founded the not-for-profit research organisation Ocean Futures Society, for which he is president.
His heart was captured by Fiji when he first came 25 years ago and visited a resort built like a traditional Fijian village called Na Koro, which translates as "My Village".
"We came and fell in love. We loved the Fijian architecture, the fact it was all made out of local materials and we loved the people."
A friend had a basic diving operation and after exploring the pristine Koro Sea, they started referring to it as the "soft coral capital of the world".
It's hard to argue given Fiji offers the largest variety of fish and coral on the planet. There are, for instance, 350-450 species of coral; by comparison Hawaii has 11.
After the original resort owners went bankrupt, Jean-Michel found investors to buy the property and agreed to put his name to it as long as it was run in an environmentally sustainable and energy-efficient way, employed Fijians and used local materials.
Since then the resort has evolved to become a multi-award winning boutique property famed for its eco credentials, its diving and its five-star Bula Kid's Club where parents can rest easy while nannies and buddies take care of their children.
The resort is the only one in Fiji that employs a full-time, onsite marine biologist, Johnny Singh, who enthusiastically imparts Cousteau's passion for the ocean to through its excellent dive school, snorkelling expeditions, glass-bottom boat rides and educational presentations. Not that we ever felt lectured to.
Over the course of a week we dive with Cousteau several times, spotting reef dwellers and large ocean pelagics (a class of fish that includes barracuda, tuna, sharks), and a huge manta ray that roves the ocean floor like a vacuum cleaner, minus his tail.
Our most memorable dive is to "Grand Central Station" at Namana Marine Reserve, which Cousteau considers to be one of the top 10 dive sites in the world. There we see a friendly hawksbill turtle, large schools of barracuda and an inquisitive sea snake who surfaces for air as we do. Located miles from the nearest developed town, this incredible dive site is home to more than 1000 species of invertebrates, 400 known corals and 445 documented reef plants.
It's also the migratory pathway for bottlenose and spinner dolphins, minke, pilot, sperm and humpback whales and is the nesting site for endangered green and hawksbill turtles. As I swim through a huge school of blue-eye jacks, large grey reef sharks circling below, I'm certain the experience will be hard to top.
To dive and dine with Jean-Michel and his wife Nancy ("Nan") is a privilege, but there are other moments I take away from a resort that offers one of the best places on the planet to learn to dive - watching Jean-Michel play with guests' children including my three-year-old Ella and teaching them about the ocean.
He patiently helped Ella collect stamps for her "Bula Passport" and entertained her with stories about meeting Nemo, Merlin and Dory when he made a guest appearance on Finding Nemo.
Each night as I tucked Ella into bed after a fun-filled day with her Fijian nanny collecting hermit crabs and spotting fish from the pier, she'd ask me to tell her a story about diving with Jean Michel and seeing Nemo.
"Tell him I'll take care of the sea," she would say earnestly and I knew he'd made another passionate convert.
Jean-Michel's granddaughter affectionately calls him Papa Frog. And he's certainly amphibious. I'll never forget him gliding through the turquoise waters, hands clasped together as if in prayer, looking completely at one in one of the world's most beautiful aquatic playgrounds.
CHECKLIST
Where to stay: Cousteau's Fiji Islands Resort is located at Savusavu on the island of Vanua Levu, Fiji's second biggest island.
Getting there: Island Hoppers offers daily charter flights to Savusavu in new aircraft.
What to do: The resort's Dive and Rejuvenation package allows visitors to stay six nights for the price of four and includes three days of two-tank dives for two adults or three days of dives for one adult and three one-hour massages for one adult (conditions apply). Rates are all-inclusive of all meals, bottled soft drinks, Fiji water, speciality teas, ground coffee, most activities, Bula Club for children 9am-9pm, exclusive nanny for each child aged five and under, Fijian buddy for children aged six-12 years, most activities and return vehicle transfers.
COUSTEAU'S TOP FIVE FIJI DIVE SITES
1. Grand Central Station
This site lives up to its name with schooling plankton feeders and larger pelagic fish including unicorns, surgeons, fusiliers and mackerels, red-tooth triggers, indo-pacific tarpons, yellowtail and chevron barracudas and big-eye jacks. Resident fish life includes Malabar groupers, spotted garden eels, black-blotched stingray and white-tip reef sharks. Hawksbill turtles, oceanic manta rays, eagle rays, narrow-barred Spanish mackerels, milkfish and dog tooth tuna can also be seen in the blue and occasionally hammerhead sharks.
2. Chimneys
On the western edge of Namena, chimneys' two pinnacles rise 30m from a coral plateau that drops into the ocean depths. Expect soft coral, colourful tropical fish, schooling unicorns and surgeonfish, blue-fin trevally, orange and pink anthias.
3. Honeymoon Rock
Similar reef topography as Chimneys, but the highlight is a hole in the first pinnacle with overhangs of soft corals and crinoids that one can safely swim through, a little bit like a wedding chapel.
4. Blue Ribbon
The main highlight is the juvenile blue-ribbon eels which, born as females, change into males during their life span.
5. Nasonisoni Pass
This drift dive is along a wall covered with every variety of pristine hard and soft corals imaginable. Divers can swim across the passage to the purple bommies, a mass of purple soft corals fed by the nutrient-rich Koro Sea waters. Large barracuda, circling grey reef sharks and white tips abound.
