Quote Originally Posted by silentenigma
i don't know, i alwayse figured they could....yuna's no athlete and she had no trouble in that quite long cutscene....and i didn't see any save spheres in that one.
They were only underwater for a brief time. Besides, one of the Besaid Aurochs specifically mentions that veteran blitzers like Wakka can hold their breath for a long time. Apparently, that's what makes them so good at their sport - they can maintain their stamina for a long time underwater, before they have to surface for breath.

If the characters could breathe underwater, then they'd surface with lungs full of water and they wouldn't be able to speak until they bubbled out several liters. It'd be plains silly.

Also, if they could breathe underwater then they'd live underwater. Which they don't.