Phione is a blue Pokémon with a round head and a tiny body. Phione's head is crowned by a flotation sac with a long, ribbon-like antenna. Its mouth is small, and its eyes are large with blue sclerae and gray irises. Above its eyes are two blue, circular markings connected to the eyes by a thin black line. Its long, flipper-like arms have rounded tips. Phione has a red, oval gem on its chest and a single rudimentary foot spike.
Phione inflates the sac on its head to drift in the water and search for food. When the water grows warm, it will drift in packs with other members of its species. No matter how far it has drifted, it will always return to the place where it was born. Sometimes it will be seen with Manaphy, visiting the Hisui region on rare occasions. Against natural predators, it uses a defense mechanism that allows it to blend with ocean waters. Phione are known to hatch from eggs laid by Manaphy, although the relationship between the two species is still unknown.
Phione's status as a Mythical Pokémon is disputed, with several pieces of evidence and even official statements often contradicting each other.
Proof from the 2011 Style Guide
Pokémon.com's mailbag was once asked[dead link] if Phione was Legendary. The official answer was initially no, but was quickly changed to yes; the whole mailbag section has since been taken down with the restructure of Pokémon.com.
Phione is listed under the Mythical Pokémon section in the Pokémon 2011 Style Guide.
In Explorers of Time, Darkness and Sky, Phione has a 100% recruit rate, is never battled, and the player is not allowed to recruit more than one to their team, all of which are traits otherwise only exhibited by Legendary and Mythical Pokémon.
In Super Mystery Dungeon, Hoopa is able to summon Phione as an ally. Only Legendary and Mythical Pokémon are able to be summoned in this way.
In Pokémon Rumble Blast, Phione can only be unlocked once a certain number of customers have shopped at the Toy Shop, a trait otherwise exclusive to Legendary and Mythical Pokémon.
Phione was featured in Pokémon.com's 2012 Pokémon Power Bracket, a single-elimination tournament where all other Pokémon in the bracket were Legendary and Mythical Pokémon.
Phione is not needed to obtain the diploma, a trait otherwise exclusive to Mythical Pokémon.
Likewise, in Pokémon Legends: Arceus, it is not required to catch Phione in order to battle Arceus, a trait otherwise exclusive to Mythical Pokémon.
Pokémon Legends: Arceus will display a warning when the player attempts to release a Legendary Pokémon, Mythical Pokémon, or Shiny Pokémon; attempting to release Phione will generate the warning regardless of Shiny status.
In the Pokémon Kids: Winter Fest badge collection all Legendary and Mythical Pokémon have special badge borders and are obtained exclusively through either opening Master pouches or clearing timed challenges. However, Phione has no special border and is obtained through standard bags in the same way all non-Legendary non-Mythical Pokémon are obtained.
In the Pokédex of Pokémon Bank, Phione does not have a shiny background, unlike other Mythical Pokémon. However, non-Special Legendary Pokémon similarly also do not have a shiny background.
Phione Eggs can be received at Day Cares and the Nursery, and it can breed to produce another Phione. No other Legendary or Mythical Pokémon can breed to produce itself.
In Pokémon HOME, the player cannot trade Phione via the Global Trade System, just like all Mythical Pokémon. Originally, even trades requesting Pokémon that could not be traded would be displayed when searching the GTS, but shortly after launch, the search was changed to not display these results. When requests for Pokémon that could not be traded were visible, even if the player chose to exclude people seeking Mythical or Legendary Pokémon, requests for Phione would still be displayed.
Phione is probably based on sea angels, specifically clione. Clione are remarkably popular in Japanese documentaries, especially in Hokkaido, on which Sinnoh is based. This may also explain their appearance in Chocovine Town.
Manaphy's trait of only being able to produce Phione as offspring may be inspired by eusociality, a biological phenomenon which usually manifests in a colony of animals having a sole breeding female, or queen, tended to by her usually infertile offspring, or an example of a highly rare and unique mutations such albinism or polydactyly. With Manaphy's title as the "Prince[ss] of the Sea" and Phione's unclear status as Mythical, it may also take influence from the illegitimate children of royalty and nobility, whose worthiness to inherit their parents' status is often disputed.
Phione may be a combination of Manaphy and Clione (genus of floating sea slugs).