Guests on Seabourn Venture – the line’s first purpose-built expedition ship, which launched last July – might have an appetite for a more adventurous itinerary, but the cluster of care‑free cruisers supping champers in the water before me is proof they’re keen to have their cake and eat it too.

Carambola Beach, a sweep of sugar sand in South Friar’s Bay – home to some of St Kitts’ most luxurious beach clubs and restaurants – seems as good a place as any to experience this decadent offering for the first time. The ship’s chefs have come ashore to set up a beach barbecue, with sizzling lobsters and giant prawns perched atop rows of hot coals. An endless glug of champagne is brought by wandering waiters both in and out of the water, and any other drink of choice is available from a makeshift bar.

Farther down the beach, the ship’s expedition team has set up a snorkel station for those keen to see what lies below the ocean’s surface. It turns out there’s a lot: South Friars Bay is one of the best areas on the island to don a mask and flippers and from Carambola Beach, swimmers can easily reach the northwest end of a teeming reef. Though heavily bleached, it boasts intact coral and lively marine life – all of which can be identified by the ship’s naturalists.

Caribbean delights

The Caribbean isn’t Seabourn Venture’s natural habitat, of course. This PC6 Polar Class vessel, which at just 132 suites feels closer to a superyacht than a cruise ship, was built for diverse environments and will spend much of the year amid the icy regions of the Arctic and Antarctica. It’s hard to imagine as I watch the vessel on the horizon – the inklings of an epic Caribbean sunset starting to form behind it – but, with a 26-strong team of expedition experts, two custom-built submarines, 24 Zodiacs that can accommodate all onboard guests and a complement of double sea kayaks, this ship is every inch the intrepid explorer.

We join Seabourn Venture halfway through a repositioning cruise between Newfoundland in Canada and Barbados, as the ship heads toward Antarctica following a successful inaugural season in the Arctic. Boarding in sunny Puerto Rico, we journey east to Jost Van Dyke, a paradisiacal port of call in the pristine British Virgin Islands. From here, cruisers can hop on a short boat ride to nearby Virgin Gorda, the third-largest island in the region and home to what is arguably the destination’s main attraction.

The Baths National Park is a veritable playground for exploring thanks to an abundance of giant granite boulders – some of which measure 15 metres in diameter. We venture along a network of narrow trails between the rocks, squeezing through tight crevices, climbing rickety wooden ladders and crouching under boulders. Our hard work is rewarded with secret rock pools; a soaring, sun-dappled cavern; and, at the end of the trail, a postcard-perfect beach, home to a tiny bar serving gin-infused coconut water straight from the shell.

Water toys

The weather takes a turn in Fort-de-France in Martinique, thwarting our efforts to sample the ship’s ample water toys. A kayaking adventure around the headland is aborted due to heavy rain, but not before the ever-perseverant expedition team has pointed out some life amid the murky skies. A brown boobie with bright yellow feet swoops down to forage some food from the sea; a lesser frigatebird glides past on long, narrow wings. High swells also put paid to our much-awaited submarine excursion, so we opt for the next best thing. An engineer sneaks us into one of two submarine hangars on board and we’re able to marvel at one of these state-of-the-art machines up close. Holding up to six guests at a time, the fully electric submarines can sink to a depth of 300 metres, with lights as powerful as a football stadium and 360-degree rotating seats installed for the full cinematic viewing experience.

Each 45-minute experience is different, but guests can expect to hover over sunken shipwrecks, observe the dark waters of the deep, or, in polar regions, come face-to-face with glacier walls. The submarines, which each cost €4 million, can’t operate in big swell or in lots of wind and ice, and their deployment is dependent on permission from local governments and maritime laws. I can’t help but wonder how these machines will fare in Antarctica if the tropical weather of the Caribbean is proving too difficult, but Seabourn appears to embrace the fact that this is an exciting work in progress.

“Guests just want to explore and they want to see what other people haven’t seen before,” one expedition team member tells me, while another describes the submarine expeditions as “100% a learning curve”. Indeed, the fact that submarines are on board at all is clearly proving a hit. “We are getting a lot of new-to-Seabourn guests,” the line’s vice-president of global sales, Steve Smotrys, says during a press conference. “Seabourn Venture is going to open up a new audience for us – those who maybe aren’t big cruisers but expeditions appeal to them. There is this great appeal for doing a more adventurous experience but then also having the luxury [element] – it’s like glamping.” Caviar in the Surf feels like a step up from glamping, but the sentiment remains. Marrying a high-impact, adventurous itinerary with familiar luxuries is surely a winning formula.

Book it: A 21-night Wild South Atlantic and Antarctica Peninsula sailing, departing on November 7, starts at £9,999 per person on board sister ship Seabourn Pursuit, which launches in August. Seabourn.com