Olympic Swimmer

In the real world, swimming is a skill that usually must be learned over a period of time - and that's just for swimming on the surface. Swimming underwater is another skill all on its own that must be learned, and even then, no human can stay under for more than a couple of minutes or so at the most without the aid of some special equipment, or some continuous training to boost lung capacity.

In fiction, however, this appears not to be the case. Video games are the biggest offender here. Any character that doesn't have Super Drowning Skills has a completely natural ability to swim like a fish, even if they've lived out in someplace like a desert their entire life.

Usually, though, they must acquire some special outfit or equipment in order to be able to swim underwater - but once they do acquire it, they are immediately able to use it like a total pro, and don't require any practice using it or moving around in the water with it whatsoever.

Then there's also the fact that in many video games, characters can swim and tread water for indefinite amounts of time without getting tired. In Real Life, swimming exerts a great amount of physical strength and energy, and gets very, very exhausting after some time, even for Olympic Swimmers (the namesake of this trope). Of course, they're also capable of walking for hundreds of miles on dry land without a break either...

This may be a somewhat Acceptable Break From Reality, however. If characters in video games had even remotely realistic swimming skills, it would take a lot of fun out of exploring Underwater Ruins and such, and not to mention it would be extremely aggravating for players.

Compare Super Not-Drowning Skills. Contrast Super Drowning Skills and Hazardous Water. See also Water Is Air.