Polar snorkelling in Antarctica with Aurora Expeditions

"Not for the faint-hearted" is how Aurora Expeditions' website describes polar snorkelling. Which is concerning because when it comes to near-freezing temperatures, I am most definitely faint of heart. Yet, here I am, fumbling awkwardly with a pair of fins on the rocky shoreline of the Antarctic Peninsula while steeling myself for water that's hovering around three degrees. Nearby, a dozen gentoo penguins look on with curious bemusement.

Aurora Expeditions has offered polar snorkelling on its Antarctic expeditions since 2014. But this is the inaugural voyage of its game-changing new ship, the Greg Mortimer, so this one-off outing is a dry-run for when it will be offered on future trips.

To ensure it really is a dry run, I'm wearing a bright-red $3000 dry suit made by Swedish diving specialist Waterproof, which has reassuringly tight silicone seals around the neck and wrists. I'm also sporting thick neoprene mittens, boots and a fetching black neoprene hood. While the finished ensemble looks like something Bond might wear on a covert mission, the grimace-inducing process of squeezing into it was more like a Mr Bean sketch.

Overseeing this excursion is guide Peter Szyszka, a Polish bear of a man who's been diving for 30 years. Clearly oblivious to the cold, he spends almost the entire voyage in a pair of shorts.

"It's cold when you first get in," he says, "but then you go numb."

With these reassuring words ringing in my ears, I cautiously edge backwards into the frigid water. To my utter amazement, it's not that bad. Two pairs of thermal underwear plus the warm air trapped inside my dry suit are a remarkably effective insulator. And then I put my head in. You know that piercing pain you get when you eat ice cream too quickly? Imagine that over your entire face.

After less than a minute, my faint heart is ready to call it a day. But then I spot a white flash out of the corner of my eye. And then another. The penguins that were watching us earlier are now in the water, fizzing around like tuxedoed torpedoes. The spectacle is so mesmerising that I somehow forget about my freezing face. That, or it's just gone numb.