Master Balls are the most powerful Poke Ball in the whole Pokemon series, as they guarantee to catch whatever Pokemon you throw one at, but they have not come to Pokemon GO yet. However, this could be changing very soon!
Currently, Pokemon GO limits players to standard Poke Balls, Great Balls, and Ultra Balls. This is unless they have won a Raid or Team GO Rocket Battle, where Premier Balls or Beast Balls are used to catch the reward Pokemon instead.
And even with the more powerful Poke Balls, you’ll still want to make excellent throws or curveball throws to increase your odds of catching Pokemon. This would make a Master Ball a huge addition to the game.
Luckily, a new Pokemon GO datamine has revealed a Master Ball Container as well as an animation for it opening. This hints that the Poke Ball with unparalleled power could be coming to the game soon!

Pokemon GO Datamine Reveals Master Ball Container
A Pokemon GO datamine conducted by PokeMiners on April 24, 2023, has found a new Master Ball Container within the game’s files.
While the Master Ball has been in the Pokemon GO game files for years now, it has never been used. However, the addition of a Master Ball Container, as well as the animation of it opening, indicates that Niantic plans on adding a Master Ball to the game soon.
As this information is datamined and not official, there’s no way of telling how Niantic would implement Master Balls yet. However, judging by the detailed animation, we expect Master Balls will be part of a Special Research Story.
Therefore, even if Master Balls come to Pokemon GO, it may only be a very rare, or even one-off, occurrence.
Hopefully, Master Balls will be a guaranteed catch, just like they are in the mainline series. Then, they would be especially handy if you want to catch all of the Legendary Pokemon in Pokemon GO!