Water Is Dry

Whenever a cartoon character falls, jumps or is pushed into water, they get right back out without any visible signs of wetness. Often the character will be fully immersed underwater — and their clothes will remain pristine and flowing. They don't need to change their clothes, nor dry themselves with a towel, nor do they seem the least bit uncomfortable in what should be sopping wet clothing. In Real Life, clothing generally tends to be very heavy, cumbersome and uncomfortable when it's wet.

The character's hair will usually also be completely, unrealistically dry. Many readers will be quite familiar with the fact that even the lightest rain can completely ruin a style and turn it into a frizzy mess.

Compare with Water Is Air.

Examples of Water Is Dry include:

Anime and Manga

Bakugan: In the episode Dan and Drago, Dan runs through the river to retrieve Drago. He's not wet when he's back on shore frolicking with Drago, and then loses his footing and falls back in the river.
In Ponyo it's explained that the title character can't get wet because she's a fish.
Cardcaptors.
Lampshaded in the Divine Design arc of the GetBackers manga: One of the things the characters learn is how to stay dry when jumping into water. Ban fails, of course, and gets soaked.
Gad Guard had a weird moment where Hajiki escaped pursuers by jumping in a sewer. He gets home in the exact same outfit he was wearing when he made the escape, perfectly dry, without so much as a lingering smell.
Pokémon seems to change the effect of water depending on episode. In the tropical Hoenn, Ash is shivering, sneezing and wrapped up in a towel after taking his clothes off after being hit by a wave on the beach, while in Pokémon 2000 Misty goes swimming fully clothed in freezing water and doesn't seem cold in the slightest. Likewise, a late Johto episode had the characters battle underwater in a pool, where they go in fully clothed, and don't appear wet in the slightest neither after getting out OR while in the pool.

Film

Star Trek IV the Voyage Home: Done when Spock swims in the whale tank.
- Averted. He wasn't wearing his robe in the whale tank and is shown putting his robe on while his undergarments are dripping. His hair is dripping for the rest of the scene.
In the 1958 film version of Cat on a Hot Tin Roof, Maggie goes out to the pouring rain and gets her hair soaking wet, but the next time we see her, it's perfectly dry and styled.
One of the (many) complaints about The Last Airbender was that in the opening scene when Katara accidentally drops water on Sokka's head, he looks almost totally dry even as he's angrily advancing on her seconds later.
In Triangle, while the other passengers on the wrecked yacht are anywhere from damp to soaked, Jess is totally dry.
In Top Secret!, after Nick Rivers wins the underwater Bar Brawl, he goes back to the surface and hails his friends. He's still standing in the river, and all his body from the belt up is completely dry.

Literature

Lampshaded and Justified in Discworld: Granny Weatherwax, after falling into a river, is dry despite standing in the middle of a downpour. Archchancellor Ridcully asks how she's doing that, and the closest thing to an answer he or the reader gets is that she's walking between the raindrops.
In Roald Dahl's short story "The Swan", Peter is not wet after wading into the lake to retrieve the swan.

Music

Touched on in the They Might Be Giants song "Particle Man": When he falls in the water, does he get wet, or does the water get him?

Video Games

Nearly every video game in which the player can swim. Making the characters look wet would require additional graphics, so the developers rarely bother unless swimming is a central element in the game.
In Kingdom Hearts II, Riku and Sora come out of the ocean just as dry as they went in. Sora's hair also is still as spiky as it was when it went in.
Averted in The Legend of Zelda the Wind Waker, The Legend of Zelda Twilight Princess and The Legend of Zelda Skyward Sword. Whenever Link gets wet, his hair and outfit will get a bit darker and he'll be dripping for a few seconds before fading to normal.
Averted in Metal Gear Solid 2: Sons of Liberty. Apart from swimming, walking on a wet floor makes your character leave footprints, and walking through rain makes him leave drops of water with a little bit of animation to show it's wet.
Averted in Assassin's Creed II. While it disappears quickly, there's a small water-droplet animation whenever Ezio gets out of the water, and his clothing is visibly wet and soggy.
Averted greatly in Tomb Raider Anniversary. The developers not only made sure Lara got wet from falling in the water but gave her realistic wet T-shirts to boot. Of course, there was a particular reason for the designers to pay attention to this.
- Not to mention she could also get dirt on her (which washed off).
- In the original series, Lara looked completely dry in the first three games when emerging from water. However, starting with Tomb Raider: The Last Revelation, she would drip when emerging from water due to the improved graphics engine.

Web Comics

From Antihero for Hire Shadehawk choses his hairspray and clothing fabric with this requirement in mind.

Western Animation

South Park: In "Free Willzyx", the boys sit in the Splash Zone at a Sea World-like Killer Whale show and get splashed multiple times. Once the show is over, they're completely dry.
Redwall
Dragon Tales

Truth in Television

A company called Liquipel has developed a technology with the same name to protect smartphones from water. When applied to a piece of tissue paper, the tissue can be dunked in water and removed COMPLETELY DRY.