Poseidon's cabin is low, long and solid, with all the windows facing the sea. The outer walls are rough gray stone with pieces of seashell and coral and look like the bottom of the ocean floor. On the inside it has six empty bunk beds and the walls glow like abalone.
Later in the series, Poseidon adds a fountain for his sons, Tyson and Percy Jackson. The fountain was made out of gray sea rock, had a fish that spouts the water from its mouth, and had a coral decoration. The bottom was filled with golden drachmas for Iris message, although it is unknown if the coins will ever run out. Percy sliced the fountain in half. Tyson later adds a few bronze Hippocampi on the ceiling as decorations. He also added unknown underwater plants and corals, sitting in the window sill, "more beautiful than the Demeter kids could whip up," Percy commented.
- Main article: Hydrokinesis
- Hydrokinesis: The ability to control water with the mind.
- They are able to breathe underwater for unlimited amounts of time.
- If they fall into water they will not be harmed.
- They are immune to water pressure.
- They have a higher resistance to fire and burns than regular people.
- They are able to make water shoot from petrified sea shells.
- When they are in salt water, they always know their exact nautical coordinates. It doesn't change if they are in water or on a ship or boat.
- They are able to create air bubbles underwater for people who cannot breathe underwater.
- They can harden water to form shields or solid ground to walk on, as seen in The Demigod Files.
- When underwater, they can communicate telepathically.
- When they are underwater, they can see in the darkness.
- They can naturally detect if water is fresh water or salt water.
- They can make giant fists of water that mimic whatever they do. This can be used to grab enemies or just smash them into the ground.
- They have the ability to walk on water.
- They can use water to strengthen themselves and heal most wounds and poisons.
- They can telepathically communicate with horses, and other creatures similar to them, all sea creatures, mythical and non-mythical creatures as well.
- They can will themselves to stay dry in water.
- They have the telekinetic ability to control boats and ships. They also know exactly how to work the boats and what all the parts and pieces do.
- Geokinesis: They have a limited amount of control over the earth. They are able to create earthquakes, as Poseidon is known for creating earthquakes.
- Atmokinesis (limited): They can create small hurricanes and other types of storms to attack others or they can use it for defense.
- Aerokinesis (limited): They have limited control over the wind. They are able to summon strong winds, which they can use to create storms such as hurricanes and typhoons.
- Electrokinesis (limited): They have limited control over lightning. They are able to use this ability to create storms, such as hurricanes, as shown when Percy used this skill unintentionally on one occasion, while creating his own miniature hurricane to fight Hyperion. Sparks of lightning appeared as his hurricane increased in power. His control of this ability, however, is far less than that of a child of Zeus and appears to be a limited side effect of his storms.
- Cryokinesis (limited): They have very limited control over ice; as shown by Percy in The Son of Neptune when he creates an icy hurricane to attack all nearby monsters.
Some legacies of Poseidon have different powers. They cannot do any of the above powers, but, if a legacy of Poseidon is from the line from Periclymenus, then they have the ability to shapeshift into animals. Other Legacies won't have this ability. It is unknown if Legacies of Poseidon will have Hydrokinesis, as Frank Zhang didn't appear to be able to use it.
- Percy has a celestial bronze sword called Anaklusmos or Riptide.
- Percy had a magic wrist watch that transforms into a shield. It was given to him by Tyson in the disguise of a watch at the end of The Sea of Monsters made by Tyson. It was lost during the Battle of the Labyrinth.
- Percy has a Minotaur's Horn which he ripped off its head while fighting the Minotaur in front of Half-Blood Hill.
- A Saltwater Fountain was provided by Poseidon for his children in the Poseidon Cabin in The Titan's Curse, until Percy destroyed it in The Battle of the Labyrinth being scared of what he was hearing and seeing (about Nico di Angelo).
Although not said to be the cabin, Percy stays in an open cabin by the beach built by his father, Poseidon. Chiron stated that Poseidon built it just for Percy, although he might have just meant all of his children, though he had no other demigod children. In the cabin, there was a life-sized trident, and many other helpful objects that Percy could use. The cabin gave an excellent view of the ocean.
- Poseidon's cabin is tied with Zeus' cabin for having the second least amount of known possible inhabitants, with each cabin having only two inhabitants each.
- However now that Thalia Grace is a Hunter, she would stay in the Artemis cabin, meaning that Poseidon's Cabin has the second least amount of occupants.