Sea days used to mean a sun lounger, a paperback and a small disagreement about who finished the crisps. These days however, some ships look more like floating theme parks that happen to have cabins too. If you're not the “towel on a deckchair at 7am” type, here are ten gloriously odd ways to spend a day at sea that don't involve bingo or queueing for the buffet.

1. Ride a roller coaster above the wake

On certain ships, “going for a stroll on deck” now includes strapping yourself into a full roller coaster that loops around the funnel. Carnival Cruise Line leads the charge here, with its Bolt coaster letting you hurtle around above the open ocean in a little electric cart while your hairdo takes 'windswept' to whole new levels.

It is short, sharp and deeply undignified, in the best possible way. You pay per ride, which conveniently stops you doing it enough times to feel queasy enough to regret your breakfast.

2. Try skydiving without leaving the ship

If the idea of throwing yourself out of a plane feels a bit much, try being blasted upwards in a glass cylinder instead. On Quantum class ships from Royal Caribbean you can book time in an iFly style skydiving simulator.

You get the whole outfit, the safety briefing, the instructor gesturing frantically at your limbs, and then a surreal minute or two of hovering in a column of air while your family films you flapping like a panicky pigeon. It is over in mere minutes but the evidence will stay in the group chat for years...

3. Do a few laps on a racetrack at sea

Several of Norwegian Cruise Line’s newer ships now come with a go kart track spiralling up on the top deck. You pull on a balaclava, climb into your kart and then spend twenty minutes pretending you are in Monaco, only with an even better sea-view.

And the best bit really is the view. There's something delightfully daft about overtaking your mates on a corner and catching a glimpse of nothing but blue water beyond the safety barriers. It feels like the sort of thing that should not exist and yet here you are, queue number 37, trying to decide on a racing nickname.

4. Go ice skating in the tropics

Walk into a real ice rink at sea is a surreal experience. Outside it's thirty degrees and the pool deck smells of coconut sunscreen. Inside, people are attempting three point turns on borrowed skates.

Lines like Royal Caribbean have had rinks for years, used both for shows and free skating sessions. The trick is to lean into absurdity. You can do sunbathing, ice skating, then a hot tub in the space of an hour, which feels a bit like cheating the seasons.

5. Fly through the ship on a zip line or ropes course

On certain big resort ships the top deck looks like someone has grafted on a high ropes centre. You clip into a harness, shuffle out onto a narrow platform, and then launch yourself along a zip line that skims over the boardwalk or pool area.

Some ships add full obstacle courses where you inch along beams, cross wobbly bridges and stare down at three decks of sunbathers who are, at that moment, very glad they chose to stay on terra firma (or whatever the shipboard equivalent of that is). It's less about the height and more about the sheer novelty of doing a mini adventure park in the middle of the sea.

6. Join a midnight stargazing session

Not every unusual sea day moment requires a helmet and signed waiver. On some itineraries, particularly in darker parts of the world, ships run simple astronomy sessions hosted by an on-board expert. You head up on deck after dinner, the crew dim the lights, and suddenly the sky's putting on a show.

Even if you've absolutely no idea where Orion is hiding, there is something special about having someone point out planets and nebulae while the ship hums along below. You can pretend you're invested in the constellations while quietly enjoying the excuse to stand outside in your dressing gown.

7. Escape from a puzzle room before sailaway

Escape rooms have made it to sea, because, at this point, what hasn't? Instead of just wandering into a lounge and ordering a drink, you'll find yourself locked in a themed room with a timer counting down and a crew member who definitely knows the answers but is not going to help.

Themes range from spy missions to haunted cabins. None of it is particularly terrifying, but there is something about a ticking clock that turns a perfectly functional group of adults into people who shout “try the key in the other drawer” at their own family members.

8. Take a behind the scenes tour that ruins nothing

For a certain sort of person, the most exciting thing on board is not the waterslides but the logistics. Engine room tours, bridge visits and backstage theatre walks pop up on many ships, usually as paid extras or loyalty perks.

You get to see the laundry that keeps several thousand towels in circulation, the galley where your afternoon cake is conjured, and the backstage corridors where the cast power walk between costume changes. Far from breaking the magic, it tends to make you appreciate dinner and a show even more once you have seen the scale of the operation.

9. Commit to an extremely serious sea day class

Most lines now offer some kind of sea day “enrichment,” which sounds rather earnest until you realise it includes things like pasta making with the executive chef, cocktail labs with the head bartender or photography workshops that finally explain how to use half the buttons on your camera.

Pick one and fully commit. You might emerge with a new signature drink, a passable bowl of handmade ravioli or at the very least a handful of stories about the time you tried to flambé something in open water. All of them beat another afternoon of scrolling social media on a sunbed.

10. Have the laziest spa day of your life

Calling the spa unusual might sound like cheating, but some of the latest shipboard wellness areas are edging into fantasy territory. Think thermal suites with heated stone loungers facing floor to ceiling windows, snow rooms to cool down after the sauna, salt grottos, hydrotherapy pools and quite possibly more water jets than strictly necessary.

Book a pass for the day and treat the whole thing like your own private members’ club. Read a book, doze between saunas, watch the horizon roll by from a bubbling pool and emerge just in time for dinner, slightly pink and very smug.

Sea days no longer have to be something you “get through” between ports. Whether your idea of fun is screaming your way around a roller coaster or spending an afternoon learning the difference between nebulae, you can now disembark at the end of the week feeling like you have done rather more than a crossword and a nap.