Oath of Poseidon

This oath revolves around the preservation of world’s oceans. 

Channel Divinity

When you take this oath at 3rd level, you gain the following two Channel Divinity options.

 Riptide 

As a bonus action, enchant a melee weapon with the soul of the ocean. For 1 minute, your weapon is wreathed in rippling water. This deals an additional 1d6 Force damage. 

This damage increase at 5th (2d6), 11th (3d6), and 17th (4d6).

Child of the Sea 

As an action become one with the sea. You gain the ability to breathe and sea perfectly underwater and gain a swim speed of 60 feet for 10 minutes. Additionally any willing creature you touch can also breathe and see under water, and you gain advantage on physical checks made underwater.

Aquatherapy

As an action, use the purifying nature of water to heal wounds. While touching water you may heal for 1d6+ your charisma modifier to yourself and a creature that you touch. 

This increases at 5th (2d6), 11th (3d6), and 17th (4d6).

Oath Spells

You gain oath spells at the paladin levels listed.

Oath of Devotion Spells

Aura of Moisture

Starting at 7th level, you and friendly creatures within 10 feet of you can’t be petrified while you are conscious.

At 18th level, the range of this aura increases to 30 feet.

Water Breathing

Beginning at 15th level, you are always under the effects of a water breathing spell.

Master of Water

Once per long rest as an action, you create a whirlpool of water that suspends you 15 ft in the air. This lasts for 1 minute. For the duration you can use tidal wave spell as a bonus action without expending a spell slot. You also gain 20 temporary hit points