Quote Originally Posted by Ifrit's_Daddy
You can question how come they can hold theyre breath for hours/breathe underwater all you like, but thats the same as questioning how come they can perform magic or how does wakka and seymour's hair stay the way it does. you dont question it, you just accept it.
HaHa! Maybe Wakka uses Aqua Net mwahaha haha ehhe

I dont think anyone breathes underwater. If you remember, when Tidus first went to besaid and was in the water, he gagged when he awakened. It also stated in that approximate time, when Tidus talks to the Aurochs at the beach, Datto says that blitzers can hold their breath for a long time (or hours). Just because someone can fight a battle or 2 underwater doesnt mean that they are breathing....remember blitzers are "battling" underwater for 10 minutes at a time, and also the characters may be swimming when in water, and not always under it.