Dimension

A dimension is any of several alternate realities or planes of existence in the Pokémon world. While trivial references to other dimensions were made early in the franchise's history, the concept was truly introduced and explored in Generation IV with Pokémon Diamond, Pearl, and Platinum.

In the core series games

Pokédex entries

Several Pokédex entries refer to other worlds and dimensions.

Pokémon	Pokédex
Haunter	Because of Haunter's ability to slip through block walls, it is said to be from another dimension.
Mega Gengar	Mega Evolution has made it possible for Gengar to access other dimensions and appear anywhere. It caused a stir one time when it stuck just one leg out of a wall. It is said that it sinks into another dimension to keep a patient watch for its chance to attack. According to the official Pokémon X and Y website, Mega Gengar's unblinking third eye allows it to see into other dimensions.^[1]
Bronzong	Some believe that Bronzong's bell-like cry allows it to open holes to another world. It brought rains through these portals and was revered as a bringer of plentiful harvests.
Porygon-Z	Porygon-Z's programming was modified to enable it to travel through and work in alien dimensions, though it did not work as planned due to an apparent error which led to noticeably strange and unstable behavior in the Pokémon.
Palkia	Palkia is said to live in a gap in the spatial dimension parallel to ours. Its total control over the boundaries of space enable it to transport itself to faraway places or even other dimensions
Giratina	Giratina is said to have been banished for its violence to live in a world on the reverse side of ours, the Distortion World, where common knowledge is distorted and strange. There, it silently gazed upon the old world. In the entry for Giratina's Origin Forme in Pokémon Legends: Arceus, Professor Laventon states that he believes Giratina "must hail from a world where the heavens and the earth are as one", though he admits he has no way of proving it.
Cosmog	Cosmog is said to be a Pokémon from another world, but no specific details are known. When it's in a jam, it warps away to a safe place to hide.
Cosmoem	People think Cosmoem may come from another world.
Solgaleo	Solgaleo is said to live in another world; at the activation of its third eye, it departs for another world. Sometimes the results of its opening an Ultra Wormhole is that energy and life-forms from other worlds are called to this world.
Lunala	Lunala is said to live in another world; when its third eye activates, away it flies to another world. It sometimes summons unknown powers and life-forms to this world from holes that lead to other worlds.
Nihilego	Nihilego is a life-form from another world that appeared in this world from an Ultra Wormhole.
Buzzwole	Buzzwole appeared from another world. Although it's alien to this world and a danger here, it's apparently a common organism in the world where it normally lives.
Pheromosa	Pheromosa is a life-form that lives in another world. Although it's alien to this world and a danger here, it's apparently a common organism in the world where it normally lives. It refuses to touch anything, perhaps because it senses some uncleanness in this world.
Xurkitree	Xurkitree appeared from the Ultra Wormhole. Although it's alien to this world and a danger here, it's apparently a common organism in the world where it normally lives.
Celesteela	Celesteela appeared from the Ultra Wormhole. Although it's alien to this world and a danger here, it's apparently a common organism in the world where it normally lives.
Kartana	Kartana came from the Ultra Wormhole. Although it's alien to this world and a danger here, it's apparently a common organism in the world where it normally lives.
Guzzlord	Although Guzzlord is alien to this world and a danger here, it's apparently a common organism in the world where it normally lives.
Necrozma	Necrozma is thought to have come from another world in ancient times.
Poipole	Poipole lives in a different world. It is well enough liked to be chosen as a first partner in its own world.
Stakataka	Stakataka appeared from an Ultra Wormhole.
Blacephalon	Blacephalon appeared from an Ultra Wormhole.

Temporal World

The Temporal World is a universe or world alternate to the Pokémon world. It is a dimension mostly composed of time and also where Origin Dialga resides in, shortly after the universe was created by the Original One.

In Diamond and Platinum, Cyrus summons Dialga from there and onto the Spear Pillar. In Platinum, when Lucas/Dawn battles Dialga after entering the Hall of Fame, it comes through a dimensional rift created by Cyrus's original summoning of it. The only known gateway to exist, is the one at the top Mt. Coronet on the Temple of Sinnoh/Spear Pillar. It has never truly appeared in the core series, only mentioned from time to time. The only Pokémon known to inhabit the Temporal World is Origin Dialga.

In Pokémon Omega Ruby and Alpha Sapphire, Dialga can be caught by Brendan/May because of a dimensional rift while soaring in the sky.

In Pokémon Legends: Arceus, Dialga emerges from a dimensional rift at the Temple of Sinnoh, where it can be battled and caught by Rei/Akari.

Its anime counterpart is quickly shown during the opening scene of Hoopa and the Clash of Ages unlike its games counterpart.

Spatial World

The Spatial World is a universe or world alternate to the Pokémon world. It is a dimension mostly composed of space and also where Origin Palkia resides in, shortly after the universe was created by the Original One.

In Pearl and Platinum, Cyrus summons Palkia from there and onto the Spear Pillar. In Platinum, when the Lucas/Dawn battles Palkia after entering the Hall of Fame, it comes through a dimensional rift created by Cyrus's original summoning of it. The only known gateway to exist, is the one at the top Mt. Coronet on the Temple of Sinnoh/Spear Pillar. It has never truly appeared in the core series, only mentioned from time to time. The only Pokémon known to inhabit the Spatial World is Origin Palkia.

In Pokémon Omega Ruby and Alpha Sapphire, Palkia can be caught by Brendan/May because of a dimensional rift while soaring in the sky.

In Pokémon Legends: Arceus, Palkia emerges from a dimensional rift at the Temple of Sinnoh, where it can be battled and caught by Rei/Akari.

Its anime counterpart is quickly shown during the opening scene of Hoopa and the Clash of Ages unlike its games counterpart.

Distortion World

Main article: Distortion World

The Distortion World is a universe or world alternate to the Pokémon world. It is a dimension mostly composed of anti-matter and also where Origin Giratina resides in, being banished there by the Original One.

In Pokémon Platinum, as Cyrus summons both Dialga and Palkia create his new world, Giratina appears from there to stop him from destroying the world, taking Cyrus to the Distortion World along with it. After Cyrus is taken away, Lucas/Dawn must follow both, and with the help of the lake guardians and Cynthia, explore the area. Two known gateways to it exist: one at the top of Mt. Coronet on the Spear Pillar, and another in Turnback Cave. It is a dark place with floor-like sections floating at many different angles. The world disobeys the normal laws of physics, allowing the player to walk and surf on walls in any direction. The only Pokémon known to inhabit the Distortion World is Origin Giratina.

In Pokémon Omega Ruby and Alpha Sapphire, Giratina can be caught by Brendan/May because of a dimensional rift while soaring in the sky.

In Pokémon Legends: Arceus, Giratina emerges from a dimensional rift at the Temple of Sinnoh to aid Volo in his battle against Rei/Akari before retreating back after their ultimate defeat, later Giratina reappeared in Turnback Cave from another rift very weakened after the previous battle, where it can be battled again and caught by them.

Its anime counterpart is known as the Reverse World and it plays an important role in Giratina and the Sky Warrior.

Arceus's realm

Arceus in its realm

Arceus's realm is an alternate dimension said to be beyond both time and space. This realm appears as a dark void where nothing appears to exist, being the world where the Original One, Arceus resides in a giant glowing appearance, supposedly its true form, similarly to the Pokémon of Myth.

In Pokémon Diamond, Pearl and Platinum, Arceus's realm can be visitted by Lucas/Dawn, specifically, the Hall of Origin, which is located in its realm, being only accessable by playing the Azure Flute at Spear Pillar, causing a glowing staircase to appear, leading a glowing platform floating above Spear Pillar and where Arceus can be battled and caught by them.

In Pokémon Brilliant Diamond and Shining Pearl, the Hall of Origin can be visitted as well by playing the Azure Flute at Spear Pillar, where Arceus be battled and caught by Lucas/Dawn.

In Pokémon Legends: Arceus, Rei/Akari are brought from the Pokémon world, to Arceus's realm where it welcomes them, transforms their phone into the Arc Phone and then sends them back in time to the Hisui region. Later on, Rei/Akari defeat Volo and with all of Arceus's Plates(except the Legend Plate) together, the Celestica Flute is transformed into the Azure Flute. Once all Pokémon are caught, Rei/Akari can play the flute and climb into the Hall of Origin, where Arceus is battled and once defeated, grants them a part of itself so it can walk with them and see world with their eyes. Even later, Rei/Akari can sleep and dream with the Hall of Origin, where they can enter the Eternal Battle Reverie, fighting several different Pokémon, including Arceus itself and its creations.

Its anime counterpart is known as Arceus's world and is quickly shown in the start of Arceus and the Jewel of Life.

The Hall of Origin(LA), located in Arceus's realm
The Hall of Origin(BDSP)

Ultra Space

Main article: Ultra Space

Ultra Space is an alternate realm similar to space, said to exist between many different worlds, each inhabited by different Pokémon, Legendary Pokémon, Ultra Beasts and even beings similar to Humans. It is a purplish-colored spatial realm with purple crystal-like meteoroids, energy spheres, electrified spheres and many Ultra Wormholes leading to different worlds, here known as Warp Holes. The only Pokémon known to inhabit Ultra Space are Cosmog, its Evolutions; Solgaleo and Lunala, and Necrozma, all possessing the ability to access Ultra Space.

In Pokémon Sun and Moon, Lusamine forces Nebby, a Cosmog, to use its power and open countless Ultra Wormholes all over Alola, causing Ultra Beasts to travel there from their homeworlds, while Lusamine and Guzma leave through one of them. Later in the games, Nebby, now as a Solgaleo^S/Lunala^M open a new Ultra Wormhole at the Altar of the Sunne^S/Altar of the Moone^M So Lillie and Elio/Selene can follow Lusamine and Guzma to Ultra Space, specifically, Ultra Deep Sea. Even later, Elio/Selene can travel through an Ultra Wormhole to an alternate Alola to find a Lunala^S/Solgaleo^M and create a new Cosmog.

In Pokémon Ultra Sun and Ultra Moon, Lusamine uses Nebby to open a single Ultra Wormhole so she and Guzma can travel to Ultra Space to capture Necrozma. Later on, Nebby as a Solgaleo^US/Lunala^UM opens a new Ultra Wormhole but before it, Lillie and Elio/Selene can go in, Lusamine and Guzma are spat out of it as Necrozma comes out, battles and absorbs Nebby, turning into Dusk Mane^US/Dawn Wings^UM Necrozma and opening countless Ultra Wormholes, causing Ultra Beasts to travel there from their homeworlds, until it is defeated by Elio/Selene, forcing it to flee through an Ultra Wormhole and into Ultra Megalopolis, but Elio/Selene then use the Ultra Recon Squad's Lunala^US/Solgaleo^US to go after it. After beating Necrozma, Elio/Selene can use either Solgaleo or Lunala to travel through Ultra Space to explore new worlds:

Ultra Deep Sea: A dark, rocky cave-like world. The only known inhabitants of Ultra Deep Sea are Nihilego.
Ultra Jungle^US: A jungle-like world full of volcanoes, normal and muscled-looking trees. The only known inhabitants of Ultra Jungle, are Buzzwole.
Ultra Desert ^UM: A whitish desert-like world with many rock-like structures and crystals, similar to buildings. The only known inhabitants of Ultra Desert, are Pheromosa.
Ultra Plant: A dark world full of mountains and in constant thunderstorms. The only known inhabitants of Ultra Plant, are Xurkitree of several different sizes.
Ultra Forest^US: A Japanese-looking forest-like world full of nature, rocks and sand. The only known inhabitants of Ultra Forest, are Ultra Forest Kartenvoys and Kartana.
Ultra Crater^UM: A huge yellowish world full of craters and gases coming out of the ground. The only known inhabitants of Ultra Crater, are Celesteela.
Ultra Ruin: A ruined, futuristic version of Hau'oli City in the Alola region. The only known inhabitants of Ultra Ruin, are an unnamed suited man and a Guzzlord.
Ultra Space Wilds: Four different worlds set in the wilderness of the Ultra Space.
- Cliff World: A reddish mountainous-like world. It is inhabited by many different Pokémon.
- Water World: An underwater cave-like world. It is inhabited by many different Pokémon.
- Rocky World: A purplish rock-covered world. It is inhabited by many different Pokémon.
- Cave World: A dark, blueish cave-like world. It is inhabited by many different Pokémon.
Ultra Megalopolis: A lightless, town-like world which had its light stolen long ago by Necrozma. It is inhabited by Ultra Recon Squad, Poipole, and Naganadel.

Ghost World

Main article: Ghost World

The Ghost World or spirit world is a location that is home to many Ghost type Pokémon and human ghosts and also implied to be the afterlife of the Pokémon universe. It is known to emit electrical or radio waves.

It has never appeared in the games, but is mentioned in all of Dusknoir's Pokédex entries and in the Japanese name of the Reaper Cloth (れいかいのぬの Spirit World Cloth), confirming its existance and a strong relation with Dusknoir.

In the side series games

Pokémon Dream Radar

Interdream Zone

The Interdream Zone

Main article: Interdream Zone

The Interdream Zone is located between dreams and reality and is investigated by Professor Burnet in Pokémon Dream Radar. The Interdream Zone is mentioned again in Pokémon Sun, Moon, Ultra Sun, and Ultra Moon by Scientists at the Dimensional Research Lab in Heahea City, which is led by Professor Burnet.

In the spin-off games

Pokémon Mystery Dungeon series

Voidlands

The Voidlands

Main article: Voidlands

The Voidlands is a realm that appears in Pokémon Super Mystery Dungeon. It is where the spirits of Pokémon who are turned to stone by Dark Matter are sent to. Beings known as Void Shadows inhabit this dimension.

In the anime

Unown Dimension

Unown in the Unown Dimension

Main article: Unown Dimension

While researching ruins with depictions of the Unown, Spencer Hale was transported into this dimension. His daughter, Molly, inherited a puzzle box found there that gave her contact with the Unown, which granted her wishes. Such was the strength of the world she created, that an opening to the dimension appeared in the entrance hall of her mansion. During this time, the Unown gained powerful control over Greenfield, but all contact with the dimension ended after Molly wished for things to go back to the way they had been before. A portal to the dimension was opened above Mt. Silver some time later, and an Unown fell out, but it had no trouble returning when it was in good health. The Unown Dimension also became the battleground of Dialga and Palkia, before their battle moved to Alamos Town.

Travel between the Unown Dimension and the real Pokémon world has been shown to be possible through a puzzle box and a portal. The direct connection between ancient sites like the Ruins of Alph and Solaceon Ruins and their large concentrations of Unown remains a curiosity amongst Scientists.

Ghost World

The portal to the Ghost World at the Summit Ruins

In the anime an entrance to the Ghost World appeared in Ghoul Daze!, where the Pokémon Summer Academy staff accidentally opened a portal to it when renovating the Summit Ruins. A ghost girl and Dusknoir were both let out, with the Dusknoir trying to take the ghost girl back to the Ghost World, while she was trying to abduct people and take them to the Ghost World. Another entrance appeared in Scare at the Litwick Mansion!, where the Litwick in Litwick Mansion tried to lead Ash and his friends there while draining their life energy.