Often in video games (and occasionally other works of fiction as well), there is no difference between swimming off the coast of Florida and swimming off the coast of Antarctica. Water is water, and the only hazard it ever presents is drowning (if even that). So you can spend all day swimming right outside Santa's workshop on the North Pole and be no worse for wear.
In real life, this is of course a good way to get hypothermia. Water that is just above freezing will sap the heat from your body much faster than air of the same temperature. Extremely cold water, such as near the poles, can even stop your heart.
Some children's cartoons and games will acknowledge the dangers of frigid waters by having a character who falls into them be be encased in a rectangular block of ice, but this doesn't seem to actually hurt them. These examples are for when a character takes a dip in freezing waters and doesn't suffer any effects whatsoever.
Sub-trope of Exposed to the Elements, and closely related to Harmless Freezing. Compare the polar opposite, Convection Schmonvection. Contrast Danger Thin Ice, Braving the Blizzard, Freeze Sneeze and Catch Your Death Of Cold, wherein being exposed to the cold does have consequences.
- Batman: In one issue, The Penguin falls through the ice at the South Pole and climbs out completely fine. This is given zero explanation (the Penguin is by all accounts a completely ordinary human), save for Batman remarking in surprise that "he's immune to the cold!"
- Tintin: In Tintin - Tintin in the Land of the Soviets, Tintin gets frozen stuck in the ice after he falls into icy water. When Snowy manages to unfreeze him, he is totally unaffected by the effects of being frozen for so long, and is even able to find the energy to fight with the Russian cossack who carried him along.
- Dragon Ball Z: Super Android 13!: Goku and company fight the trio of androids in the Arctic. Nobody involved suffers from the cold of the Arctic or frequently being knocked into the freezing water.
- How to Train Your Dragon 2: Hiccup gets snatched up by Valka's dragons and, because Toothless needs Hiccup to fly via his artificial tail-fin, Toothless ends up careening miles out of the air into a thick sheet of ice, breaking through into the freezing ocean. He is then brought to Hiccup completely fine.
- Ghost Ship ends with Epps, the Sole Survivor of the salvage crew, clinging to debris in the Bering Sea, which has an average temperature of 34-41 F. It's not specified how much time she spends adrift before a passing cruise ship picks her up, but realistically she would only have survived for two hours.
- In Lara Croft: Tomb Raider, the final piece of the MacGuffin is in Siberia. Lara shows up in a shirt and pants that aren't much heavier or cover her any more than what she wore in Cambodia, and even takes a swim in an underground pool of water to no ill effect.
- Game of Thrones: In Season 7, Jon Snow is knocked into the frigid waters of a frozen lake. Despite being submerged for quite some time, he survives just fine, even when he has to wear his thoroughly drenched clothes in winter weather on a long ride back to the Wall afterwards.
- In The Pirates of Penzance, Major-General Stanley's daughters suffer no ill-effects from dipping in the English Channel in February.
- Dungeons And Dragons: According to the Frostburn sourcebook, if you have Cold Resistance 5, you are immune to natural cold climates, making this a Justified Trope.
- In GURPS, enough levels of Temperature Tolerance (Cold) make you effectively immune to hypothermia. Normal humans can get at best two levels there, which, if your character is decently fit, is enough to be just fine up to 11°F/-11°C. All bets are off if your character is not quite normal.
- ABZÛ: The final sequence takes place in the Arctic ocean, complete with drifting ice, penguins and polar bears. The protagonist is not deterred by the temperatures in the slightest, though this is justified as she is actually a humanoid robot with superhuman resilience.
- Animal Crossing: New Horizons: You can swim in the ocean even when it's winter in your hemisphere and the snow on the ground indicates that the water must be cold. You wear a wet suit, but, generally, dry suits are needed for colder water, and one of the suit options has shorts on the bottom while others are sleeveless.
- Donkey Kong Country: The level "Croctopus Chase" takes place in the waters of Gorilla Glacier, but neither Donkey nor Diddy (both who should not even be swimming to begin with since most apes are very poor swimmers) are negatively affected by it. Ditto for the ice cave levels in the sequel that feature lots of water.
- Ecco the Dolphin: One of the levels is a combo of Under the Sea and Slippy-Slidey Ice World set in the Arctic. Bottlenose dolphins like Ecco usually live in water that's about 50°F/10°C at the coldest, yet Ecco seems unaffected. It could hypothetically be chalked up to some sort of help from the Asterite but there's no in-game explanation for it.
- The Elder Scrolls V: Skyrim: The Dragonborn suffers no harm from swimming in the icy northern oceans. While this may be justified in the case of Nords, who have a 50% racial resistance to cold damage, the other Player Character races have no such excuse. The popular Frostfall Game Mod averts this, as getting into cold water, especially in the northern regions, is extremely dangerous and potentially fatal, depending on the mod's settings. At best it hits you with serious penalties to speed and skills, and by default it renders you unconscious in a matter of minutes, even if you get out of the water quickly.
- Endless Ocean: Two of the dive locations of Blue World are the Arctic and the Antarctic. There is a handwave about body gel that helps with cold weather, and special air tanks or something, but no mention of a dry suit. Considering the character's costume can be changed to a bikini (for women) or just a pair of trunks (for men), you can very well go diving in those places thusly garbed and suffer no ill effects.
- In EverQuest, the snow-filled Barbarian city of Halas is separated from Everfrost Peaks by a lake. The only way to get into or out of the city is to cross the lake. There is a raft that automatically sends players back and forth, but most players just choose to jump in and start swimming instead of waiting for the delay in the raft. Barbarian characters start off almost completely naked save for a kilt (and matching top for women), yet suffer no ill effects from diving right in.
- In EverQuest II, the continent of Everfrost's zone-in point places you on a large dock attached to an island that is separated from the rest of the continent. Before the ability to fly was put into the game, players had no choice but to jump into the shark-infested waters and swim to land. The local explorers complain about the cold to no end, but swimming around doesn't affect adventurers except for the occasional shark attack.
- The Legend of Zelda: Played straight in most games, with a few notable exceptions.
- The Legend of Zelda: Ocarina of Time: Link can spend all day swimming in the waters of Zora's Fountain after it gets frozen over.
- The Legend of Zelda: The Minish Cap: The Temple of Droplets is an icy dungeon that has pools of water Link can swim in safely. In fact, Link has to shrink to enter that dungeon, so he should be freezing even more quickly than he would at normal size.
- The Legend of Zelda: Breath of the Wild: Averted. Ordinary water is only a minor hazard, at most removing one unit of Link's health if his stamina runs out while swimming, and it even breaks a fall harmlessly, but water in cold environments steadily saps his health to the point of death, even with protective clothing.
- Metroid: Played straight for the most part throughout the series, where Samus suffers no ill effects from walking in water in icy locations (minus the gravitational effects) even with the most basic power suit on. Averted somewhat with the Fusion Suit, as Samus will take damage from merely being in cold areas until she acquires the Varia Suit.
- Sonic the Hedgehog: In any given game, either all water is instant death or all water is safe for underwater platforming, regardless of temperature.
- Sonic the Hedgehog 3: Downplayed. Water in Ice Cap Zone doesn't hurt you, but it's only found at the lowest points of the level, over Bottomless Pits, so you're unlikely to spend more than a few seconds in that water.
- In Sonic Adventure, Big the Cat's second stage is Ice Cap, which requires him to break through the ice in order to fish in its waters and catch Froggy, his pet frog. The fish living inside the water as well as Froggy are perfectly fine swimming inside it, and the only thing Big has to fear is drowning, especially if he didn't collect the Life Belt upgrade which allows him to swim before entering the stage. In the B and A Rank missions, Big has to swim through the secret passage under the water to get to a room where bigger fish required to complete the missions are stored.
- Sonic Advance: Played straight with Ice Mountain Zone and Twinkle Snow, respectively in the first and third games, which are both half-underwater and allow to swim freely in the icy water.
- Spyro the Dragon: Spyro can swim in freezing water in worlds like Winter Tundra, Icy Peak and the Icy Wilderness indefinitely.
- Super Mario Odyssey is another aversion as the Snow Kingdom's water will cause rapid health drop unless Mario captures one of the Cheep-Cheeps.
- Wario Land: Super Mario Land 3: The frozen Sherbet Land has a few underwater levels, where the water behaves exactly the same as in every other world.
- Yooka-Laylee: Yooka the chameleon can swim in the Glitterglaze Lake in the Glitterglaze Glacier level with no ill effects despite being a cold-blooded animal.
- Peppa Pig: One episode has the characters going to the beach in the snow, and Madame Gazelle swims in the sea with her swimsuit on and doesn't get hypothermia. While the others don't want to swim due to finding it unpleasantly cold, hypothermia isn't brought up.
- This is a test of character and resolution for the Royal Marines (trained by Britain as an arctic and winter warfare force: their role in any World War Three would be to support and fight alongside Norwegian troops in Scandinavia). The Marine is completely immersed in Arctic water for thirty seconds or so, hauls himself out, and then has to take the appropriate course of action to avert hypothermia.