AD&D 2nd Edition

Sphere: Elemental (Water, Air)
Range: Touch
Components: V, S
Duration: 1 hour/level
Casting Time: 6
Area of Effect: Creature touched
Saving Throw: None

The recipient of a water breathing spell is able to breathe under water freely for the duration of the spell – i.e., one hour for each experience level of the caster. The priest can divide the base duration between multiple characters. Thus an 8th-level priest can confer this ability to two characters for four hours, four for two hours, eight for one hour, etc., to a minimum of 1/2 hour per character.

The reverse, air breathing, enables waterbreathing creatures to survive comfortably in the atmosphere for an equal duration. Note that neither version prevents the recipient creature from breathing in its natural element.