The Legend of Zelda: The Wind Waker/Unused Link Animations
This is a sub-page of The Legend of Zelda: The Wind Waker.
While Link's swimming animation is used, the fact that the game's water is opaque means that players can normally only see his head. The fact that he is fully animated is mostly hidden from sight. However, certain test rooms do use transparent water, suggesting that this was not always the case.
Arguably this is not "unused" as Link's shadow is projected upwards onto the water.
Interestingly, if you L-target and swim left, right, or backwards, Link will use the same animations as he would on land.