Ultra Space

Ultra Space (Japanese: ウルトラスペース Ultra Space) is the home of Ultra Beasts, accessible via Ultra Wormhole. Professor Burnet is researching these strange phenomena.

Geography
Ultra Space is an interdimensional spatial realm filled with crystalline meteoroids and populated by and multiple instances of members of the  line. It links to a number of different universes and dimensions through Ultra Wormholes - while they may naturally occur, they are more commonly deliberately opened up by the Light trio.

History
In ancient times, Necrozma's light shone through the Ultra Wormholes connecting to various worlds such as the Ultra Beasts' homeworlds, Ultra Megalopolis, and the Pokémon world, primarily over the Alola region. However, following an incident with the residents of Ultra Megalopolis years ago, Necrozma's body was damaged and it lost the ability to produce light, the agony caused by its injuries sending it into a berserk state where it constantly hungered for light. As a result, it was imprisoned in Megalo Tower. Professor Kukui theorizes that the Sparkling Stones found across Alola and fashioned into Z-Power Rings are the lost pieces of Necrozma's body.

At one point in the past, a Solgaleo/Lunala arrived in Alola from Ultra Space and won a fight against the guardian deities. Solgaleo/Lunala bestowed the Tapunium Z to the guardian deities, and in conjunction with a Lunala/Solgaleo produced several that were revered by the region's monarchies and protected by the four tapu, before the Legendary Pokémon departed back to Ultra Space.

At another point in the past, Necrozma appeared in Alola and stole its light, covering the region in darkness. Necrozma clashed against the guardian deities, who fought to defend Alola. During that time, Necrozma also absorbed Solgaleo/Lunala to become its Dusk Mane/Dawn Wings form. With the assistance of a youth, Z-Crystals and Sparkling Stones, the deities banished Necrozma, freed Solgaleo/Lunala, and reclaimed Alola's light.

Pokémon Sun and Moon
The player is only able to visit the home of, Ultra Deep Sea (referred to as Ultra Space), in order to save Guzma and Lusamine from an Ultra Wormhole at the Altar of the Sunne/Altar of the Moone.

Pokémon Ultra Sun and Ultra Moon
The following areas can be accessed by merely interacting with the Ultra Wormhole at the Altar of the Sunne/Altar of the Moone:
 * Reverse world
 * Ultra Megalopolis
 * Megalo Tower

Unlike in Sun and Moon, the player can travel through the Ultra Wormhole with or  using Ultra Warp Ride and access several new Ultra Space areas. The following areas can be accessed this way:
 * Ultra Deep Sea
 * Ultra Jungle
 * Ultra Desert
 * Ultra Plant
 * Ultra Forest
 * Ultra Crater
 * Ultra Ruin
 * Ultra Space Wilds
 * Cliff World
 * Water World
 * Rocky World
 * Cave World

If a, or  is evolved in Ultra Space, it will instead evolve into Kantonian ,  or  rather than their respective Alola Form.

In the anime
In Revealing the Stuff of Legend!,, , and traveled through an Ultra Wormhole with Nebby to the Ultra Deep Sea to rescue Lusamine from. Everyone escaped the Ultra Deep Sea and returned to their own world in 10,000,000 Reasons to Fight!

An unnamed, anime-exclusive world in Ultra Space made its debut in a dream The Shape of Love to Come!. It is the home world of Ash's Poipole. In The Prism Between Light and Darkness!, the Ultra Guardians arrived in this world with in pursuit of, where it was revealed that Necrozma used to grant light to this alternate world before it lost its power protecting its residents. With the combined Ultra Aura of the people and Pokémon of Alola, Necrozma was able to return to its Ultra form, bringing life back to the world. Its mission complete, Ash's Poipole decided to stay with its kind, bidding Ash and farewell.

In Battling the Beast Within!, Ash and Pikachu were transported through a dimensional rift to the Ultra Ruin, an alternate version of Alola that was devastated by the arrival of a. The pair came face to face with Guzzlord, but were rescued by and his friend. Ash and Pikachu later assisted Dia and Zeraora in pushing Guzzlord into an Ultra Wormhole before returning to their own world in Parallel Friendships!.

In the TCG
This listing is of cards mentioning or featuring Ultra Space in the Pokémon Trading Card Game.

Trivia

 * fails if the player tries to use it here.

In other languages
Ultradimension Ultraespacio Ultra-Dimension Ultramondo ウルトラスペース 究極空間