A variety of arcane colleges specialize in training wizards certain subjects, but few truly focus on an element, and even fewer choose this one. The Art of the Endless Tides blends principles of nearly every school, rather than specializing in any of those schools. It teaches techniques that empower a caster’s aquatic abilities, in both melee and ranged battles.

Entrapping Tides

Beginning when you select this subclass at 2nd level, when you hit a creature with an attack using a weapon, you can invoke the sea to summon watery tentacles: the target takes an extra 2d6 bludgeoning  damage, and it must succeed on a Strength saving throw or be restrained until your next turn. While restrained by the shackles, the target takes 2d6 bludgeoning damage at the start of its turn. The target can repeat the saving throw at the end of each of its turns, banishing the shackles on a success.

You can only use this feature each long rest an amount of times equal to your proficiency bonus.

Wavelord

Beginning at 2nd level, you can create tides upon the overworld. 

As a bonus action, you can create and move a wave of water up to 30 feet. If you ram the wave into a creature, that creature must make the saving throw against the wave’s damage or be pushed with it. When you move the wave, you can direct it over barriers up to 5 feet tall and have it cross pits up to 10 feet wide.

This wave of water takes concentration to maintain. You can only use this an amount of times equal to your Intelligence modifier each long rest.

Protection of the Deep

Beginning at 10th level, you can expend one use of your Wavelord ability to create a shield of water around yourself as a reaction. Add your Intelligence modifier (minimum of 1) to your AC and all saving throws you make until your next turn.

Leviathan

Starting at 14th level, as an action you can Leviathan as an ally for one minute. Leviathan appears in an unoccupied space you can see within range, and disappears when it or you drops to 0 hit points. You can do this once per long rest.