Rarest Shiny Pokémon GO are the rarest of the rare. These Pokémon were released either only once or are region locked, making them extraordinarily difficult to find. Here are three of the rarest Shiny Pokémon in Pokémon GO.
Rarest Shiny Pokémon GO: Three Rarest Shiny Pokémon
Deino is extremely hard to find in the wild, and even rarer from Eggs. It's incredibly difficult to capture a normal one, let alone a Shiny. The event where Deino was featured didn't help either, with spawn rates being still incredibly low.
Another are fifth-gen Pokémon, Yamask was only available as Shiny during a Halloween event. It was still extremely rare during the event, making Shiny Yamask among the rarest by virtue of unavailability. As of writing, Shiny Yamask is no longer available in the game.
Unown has many different forms, only released during certain events. Even rarer are Shiny forms of the letters. Only the most devoted Trainers should commit to collecting the entire set as Shiny, as some of the events will inevitably be local for different regions.
Honorable Mention: Costumed Pokémon
Only some costumed Pokémon, like Pikachu wearing hats, can be Shiny. These Pokémon are released for special events and typically can't evolve. Many of them are timed exclusives, so if you missed out on them before it would be unlikely you would be able to find them again.