Super Mario series
Swimming is a staple mechanic of the Super Mario series, first being possible in Super Mario Bros. and going on to be in every mainline title except Super Mario Bros. 2, Super Mario Land, and Super Mario Run. In the 2D games, swimming mechanics have remained largely unchanged; Mario naturally sinks in water and swims upwards when the player presses the jump button, preserving his forward momentum. There is no air meter, allowing Mario to stay underwater indefinitely.
In the 3D games from Super Mario 64 through Super Mario Galaxy 2, the swimming mechanics are different. Mario is aimed in any direction by using the Control Stick, with the jump button propelling Mario forward in that direction. He does not naturally sink in the water when not actively swimming. Additionally, an air meter is added, which causes Mario to take damage and eventually drown if he is underwater for too long without collecting an air bubble. In Super Mario Galaxy and its sequel, Mario is able to use the Star-Spin to propel through the water faster than normal swimming. When the player plays as Luigi, he loses air with every Star-Spin. Both brothers can also quickly dive directly downwards while underwater when the player uses .
Starting in Super Mario 3D Land, the swimming mechanics are changed to imitate the mechanics of the 2D games. Mario gains the ability to ground-pound underwater, replacing the Super Mario Galaxy games' diving move. Super Mario Odyssey maintains the rising-and-sinking swimming, but it includes the air meter. Mario can also use the new Quick Swim move with + , which propels him forward similarly to the Star-Spin in Super Mario Galaxy.
Several items and power-ups allow Mario to swim faster or with more control. The Frog Suit in Super Mario Bros. 3 and Super Mario Maker 2 and the Penguin Suit in New Super Mario Bros. Wii and New Super Mario Bros. U allow Mario to automatically swim much faster when the player holds down a direction and/or the jump button, akin to the early 3D games. The Blue Shell in New Super Mario Bros. increases Mario's swimming speed and precision. In the 2D games from Super Mario World onwards, Super Mario 64, Super Mario Galaxy, and Super Mario Galaxy 2, grabbing a shell allows Mario to automatically swim forward in the water very quickly. In Super Mario Sunshine, using the Hover Nozzle underwater propels Mario forward. In Super Mario Odyssey, capturing a Cheep Cheep allows Mario to swim through the water quicker and without regard for the air meter.
In Super Mario Maker 2, in the nighttime version of the castle theme, Mario and the other playable characters are able to swim in midair with the same mechanics as water.
Donkey Kong Country series
Swimming has been a part of the Donkey Kong Country series since the first game. In the SNES games, the Kongs can swim through the water just as Mario does in the 2D Mario games. They are helpless underwater without the help of Enguarde, who can move with only , as well as dash forward and stab enemies with his sharp bill.
Donkey Kong and Diddy Kong are unable to swim in Donkey Kong Country Returns; the Kongs simply lose a life when touching water. Swimming is brought back in Donkey Kong Country: Tropical Freeze, where the Kongs are able to swim in 360 degrees, as well as use a new spinning attack when the player presses the roll button, though they now have an air meter, which is refilled with bubbles. Dixie Kong is able to propel faster underwater with her hair. If two Kongs are paired up, they can perform an infinite Kong Corkscrew; in the Nintendo Switch port, Funky Kong can also do so on his own. Funky also has no air meter, as he wears swimming goggles.
Yoshi can swim on the water's surface and underwater in all of the Yoshi games except Yoshi's Crafted World, where he instead drowns if he jumps in water, though Poochy and Poochy Pups are able to swim in that game as well as Yoshi's Woolly World. In that game, Yoshi's feet turn into a propeller when he swims at the surface, and he can swim underwater as Mermaid Yoshi.
Super Smash Bros. series
In Super Smash Bros. Brawl, Super Smash Bros. for Wii U, and Super Smash Bros. Ultimate, fighters are able to swim across water. However, they will drown if they remain in the water for too long and lose a stock, the time required based on the character's percentage. In Super Smash Bros. Ultimate, Charizard, Sonic, Inkling, and Incineroar take a small amount of damage while swimming. There are stages in Super Smash Bros. Melee and Super Smash Bros. for Nintendo 3DS that include water; however, fighters simply fall through it. These stages' water is made swimmable in their Super Smash Bros. Ultimate incarnations.