The Ultra Beasts (Japanese: ウルトラビースト Ultra Beast) are a group of extradimensional Pokémon originating from Ultra Space. They possess power that transcends humans' understanding of the world.

Ultra Beasts infrequently appear from Ultra Wormholes in Alola. These appearances are apparently as unexpected for the Ultra Beasts as for Alolans, which tends to make them combative. They are especially drawn to people who have passed through an Ultra Wormhole, due to the residual wormhole energy on them, apparently expecting to find a wormhole they can use to return home.

Most Poké Balls have difficulty recognizing Ultra Beasts as Pokémon due to their extradimensional origins, impairing their ability to effectively catch them. Beast Balls, being specifically designed to catch Ultra Beasts, are instead ineffective against Pokémon that are not Ultra Beasts. The Master Ball is unaffected by this impairment due to catching any Pokémon without fail, even Ultra Beasts.

The Ultra Beasts are all canonically genderless. They all share the Ability Beast Boost.

Ultra Beasts:

• Nihilego (codenamed UB-01 Symbiont)
• Buzzwole (codenamed UB-02 Absorption; exclusive to Sun and Ultra Sun)
• Pheromosa (codenamed UB-02 Beauty; exclusive to Moon and Ultra Moon)
• Xurkitree (codenamed UB-03 Lighting)
• Celesteela (codenamed UB-04 Blaster; exclusive to Moon and Ultra Moon)
• Kartana (codenamed UB-04 Blade; exclusive to Sun and Ultra Sun)
• Guzzlord (codenamed UB-05 Glutton)
• Poipole (codenamed UB Adhesive; exclusive to Ultra Sun and Ultra Moon)
• Naganadel (codenamed UB Stinger; exclusive to Ultra Sun and Ultra Moon)
• Stakataka (codenamed UB Assembly; exclusive to Ultra Moon)
• Blacephalon (codenamed UB Burst; exclusive to Ultra Sun)

Note: While Cosmog, Cosmoem, Solgaleo, Lunala and Necrozma are said to come from Ultra Space, they do not fall under this tag as they are not classified as Ultra Beasts by the in-game Pokémon capturing mechanic.