This guide will let you know what Aqua Affinity does in Minecraft.
Aqua infinity is an armour enchantment; you can only apply it to a helmet.
It allows you to mine and dig underwater at the same speed you would on land.
Aqua affinity is ideal for anyone who wants to dig out large areas underwater. It is recommended to use potions of water breathing for long term digging or mining underwater.
Efficiency enchantments will also work with aqua affinity.