How do you get water tunic?

Answer 1

if you're playing zelda: ocarina of time then you need to go to the ice caverns, where jabu jabu used to be and catch blue fire in your empty bottle...then head back to the zora king, now frozen in red stuff...empty the blue fire on him and he'll give you the zora's tunic...if you're playing zelda: twilight princess then you need to climb the top of zora's river after beating the fire temple...once the zora queen's spirit speaks with you, you need to head to kakoriko graveyard and climb through the small hole to the other side...then cross the water and open the grave to find the zora's armor underneath

Answer 2

In the ocarina of time, you can get it by either unfreezing king zora, or by buying it in the zora market.