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. Tyson later adds a few bronze Hippocampi on the ceiling as decorations, along with unknown underwater plants and corals, sitting in the window sill, "more beautiful than the Demeter kids could whip up." Later, Poseidon adds a fountain made out of gray sea rock with a fish that spouts the water from its mouth and coral decoration. The bottom was filled with golden drachmas for Iris message, although it is unknown if the coins will ever run out. Percy later sliced the fountain in half in The Battle of the Labyrinth.
In the graphic novel, the cabin has a sea shell over the door and waves on the top. A nightstand sits next to the bunk and a lamp is stuck to the wall near the top bunk. The fountain appears to be made of a red sea rock. A light blue couch sits next to the window.
In The Battle of the Labyrinth graphic novel, the cabin appears as looking like a Greek temple with columns, waves on the top, and a trident over the door. The bunks have light blue bed sheets with waves on them and two seashells next to the door on either side.
In the film adaptation, Poseidon's cabin is open and wooden with a Trident over the entryway and two banners with a Trident on it and says Poseidon's Cabin on it. There are also tent canvases on the windows for privacy. Inside the cabin, it has a hammock, chairs, desks, a life-sized metal Trident, scrolls, and a book. There is also a steering wheel, a telescope, and lanterns. The cabin leads to a personal dock. The cabin is built near the beach and has an excellent view of the lake.
- Atmokinesis: They have limited control over the weather. They can create small hurricanes and storms to attack others or for defense.
- Hydrokinesis: The ability to control water with the mind. They can will themselves to stay dry in water, extract water shoot from petrified seashells, create oxygen bubbles underwater for people who cannot breathe underwater, and harden water to form solid ground to walk on or shields. They even can make giant fists of water that mimic whatever they do, which can be used to grab enemies or smash them into the ground.
- Cryokinesis (limited): They have very limited control over ice; such as create an icy hurricane to attack all nearby monsters.
- Vitakinesis (limited): They can use water to strengthen themselves and heal most wounds, the amount of water and time needed for the healing being proportionate to the severity of the wound.
- Water Immunity: If they fall into the water, they will be immune to water pressure. Additionally, they can breathe underwater for unlimited amounts of time and see in the darkness underwater.
- Heat Immunity (limited): They have a higher resistance to fire and burns than regular people.
- Watercraft Manipulation: When they are in saltwater, they always know their exact nautical coordinates, wherever they are (such as in water or on a ship or boat). They have the telekinetic ability to control boats and ships. They also know exactly how to work the boats and what all the parts do.
- Aerokinesis (limited): They have limited control over the wind. They can summon strong winds, which allow them to create miniature hurricanes and typhoons.
- Electrokinesis (limited): They have limited control over lightning, such as sparks as their hurricane increases in power. Their control, however, is far less than that of a child of Zeus.
- Geokinesis: They have a limited amount of control over the earth. They can create earthquakes as their father is known for creating them.
- Communication: They have divine authority over their father's subjects and can speak both telepathically and normally with each other underwater.
- Zoolingualism (limited to Equestrians and Marine Life): They can understand and talk to marine animals, equines, and similar creatures.
Some legacies of Poseidon have different powers. If a legacy of Poseidon is from the line from Periclymenus, they can shapeshift into animals. Other Legacies won't have this ability. It is unknown if Legacies of Poseidon will have Hydrokinesis or any of the other powers children of Poseidon have displayed, as Frank Zhang didn't appear to be able to use it, though this maybe because it is mentioned Poseidon blessed their family line with the power and it wasn't by chance.
- A Saltwater Fountain filled with golden drachmas in The Titan's Curse. It was destroyed by Percy in The Battle of the Labyrinth.
- Percy's Celestial Bronze sword called Riptide. It is enchanted to appear in his pocket if it is somehow lost.
- Percy's wristwatch that transforms into a shield created by Tyson. It was lost during the Battle of the Labyrinth.
- A special, light javelin created by Tyson that Percy uses in the Chariot Races.
- Poseidon's Cabin blue chariot
- Athena and Poseidon cabin's chariot
- Percy's Minotaur horn obtained in the battle in front of Half-Blood Hill.
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. Still, 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.