Hạ Long Bay is a ridiculously beautiful part of the world. Thousands of limestone karsts tower out of the clear blue water, in which secluded white beaches nestle among caves worn by millennia of waves. It is a stunning, magical place.

Before planning our trip to Hạ Long Bay, we had carried out some careful research. The bay has earned a reputation for being full of rowdy tourists, often to the point where you can barely see the water for boats. We didn’t want to encounter (or add to) the problem, so opted instead for a little private boat for the two of us, in which we would explore to the quieter waters of Bai Tu Long Bay and Lan Ha Bay, with only a brief glimpse of Hạ Long Bay itself.

Our little boat was based at a tiny harbour on Cat Ba Island, and as we stepped off the hydrofoil from the mainland onto the pier, we met our crew for the next three days. A chap called Hiến would be our guide, accompanied by our captain, who would navigate us around the bay, and a chef who would be cooking for everyone on board.

As we climbed aboard the Dolphin Junk, Hiến gave us a tour of our home for the next few days. It was fairly basic, but very comfortable. We had our own little bedroom with a double bed, and an ensuite with a warm shower. At mealtimes we would eat in the main room of the boat, just alongside the captain sitting at the wheel. The top deck had a sun lounger big enough for the two of us, shaded with a woven awning. The Dolphin Junk was exactly what we had hoped for: an seemingly authentic, tourist-free way to explore the bay. No air conditioning, no DJs and no all-you-can-drink cocktail bars. Pity.

Our time sailing around the bays was absolutely relaxing, picturesque and awe-inspiring. There are over 2,000 karsts dotted around the bay in all shapes and sizes; Ha Long means ‘descending dragon’ in Vietnamese, and locals have names for individual rocks which Hiến occasionally pointed out as we sailed past. The seascape changes with every turn, and we gently motored around the rocks, watching the sea birds twist and whirl around the rocky outcrops.

Sunset in the bay is equally beautiful, with the sky blazing in a thousand shades, reflecting on the rippling water. I don’t think I’ve ever eaten dinner in a more wonderful spot.

At night, the captain headed towards a quiet cove, threw the anchor overboard, and the Dolphin Junk gently circled the anchor as the tide ebbed and flowed around us. Far from the light pollution of Hanoi, the sky was pinpointed with thousands of stars. We sat on the top deck, listening the calls of small animals and birds from a nearby karst and playing cards by the light of our head torches.

The food on the boat was delicious, and the chef did a great job. With freshly caught fish, crispy noodles, and even tofu that tasted of something, we ate like kings three times a day, watching the ever-changing scenery gliding by the windows of the junk.

One afternoon we stopped off at the captain’s parents’ house, where they live on the edge of a floating fishing village. Well into their 70s, they make their living catching fish and seafood from their tin house, which floats on oil drums and foam pontoons. Many of the families who live in these little floating villages barely ever set foot on dry land; fresh water arrives on a monthly barge, and a little market boat paddled by an elderly woman comes around most days with supplies of beer, wine and basic ingredients. Our captain picked up a bag of small black shells from the captain’s parents, which were served up less than an hour later by the chef: hot, steaming clams abundant with soy sauce and fresh herbs.

At one point we boarded a slightly larger boat, which was painted white; safety regulations in Hạ Long Bay mean that all boats in the area need to be white. We sailed into the middle of the bay, and it looked very similar to the other bay we had explored. Geologically, they are the same, but they are named differently as they fall into different Vietnamese provinces. Our day in Hạ Long Bay was also our closest brush with other tourists, as a few of the dreaded party boats spluttered by, crammed full of blistered westerners, accompanied by the dull thump of dance music. We were so pleased to have a boat all to ourselves.

As we sailed around the karsts, our boat would sometimes slow to a stop, then Hiến would appear, stand atop the boat and check the sea for jellyfish. Once he had determined it was clear, he’d give the okay for us to jump into the water. Even with the sea breeze, it was well over 35° on the boat, so it was a relief to jump into the water and swim around to cool off.

The Dolphin Junk towed a couple of little kayaks as it went, which every so often we climbed into, and went off to explore the caves, coves and the white sandy beaches. On one kayak trip, Hiến directed us towards some rocks which concealed a narrow tunnel through a karst. We paddled through into shallower water, and emerged into a lagoon surrounded entirely by tall cliffs. It turns out the warmer water in the lagoon makes it a perfect breeding ground for jellyfish. And breed they certainly had. The place was completely packed with baby jellyfish bobbing around just under the surface. Up until this point, I’d been consistently splashed with every single stroke of Nicola’s paddle, but hadn’t really minded. When it became clear that these splashes would now involve venomous sea creatures being flung towards me, I politely asked Nicola to stop paddling, which she was understandably very miffed about.

We had got quite used to our lives living on the Dolphin Junk, so were sad when our intrepid little voyage came to an end, and it was time to return to Cat Ba Island. After a final trip through the floating fishing villages of Cat Ba, we bid farewell to Hiến and the rest of the crew, and set off towards the mainland, for a few final days exploring Hanoi.

We explored the bay with: Cat Ba Ventures (catbaventures.com)
We took the hydrofoil to: Cat Ba Island (lonelyplanet.com/vietnam)
We stopped for food at: The Captain’s Parents’ House. They don’t have a website.