In Pokémon Go, that's so far been limited to Pokémon Go Fest Chicago 2018, but it won't be long before Celebi is available to quest for around the world.
I cannot catch celebi on my phone. Here's how to navigate the Ripple in Time campaign to catch Celebi. Like the Generation 1 Mythical, Mew, encountering Celebi requires you to complete Special Research. Pokémon Go has released another mythical Pokémon. Pokémon Go has released another mythical Pokémon. If I try to catch it without AR on, I get this weird image of celebi that is uncatchable and keeps disappearing and reappearing.
Celebi is the Mythical Pokémon of Generation 2, first discovered in the Johto Region. Here's how to navigate the Ripple in Time campaign to catch Celebi. AR mode has never worked on my phone (it shows the AR picture but no Pokemon will appear on it) for some unfathomable reason the game says you must catch celebi in AR mode.