As of June 2021, Galarian Slowking is unavailable in Pokemon Go, meaning that it cannot be evolved either.
Galarian Slowking is a poison and psychic who has an easygoing personality. It is a direct evolved form from Galarian Slowpoke. It is also one of the few Pokemons that has Region Forms.
Galarian Slowpoke, the original form of Slowking, made its debut in Pokemon Go during "A Very Slow Discovery" challenge on June 8, 2021 at 9 a.m. ET.
How to Get Galarian Slowking in Pokemon Go
The Galarian Slowking is unavailable in Pokemon GO. Slowpoke can evolve into a Galarian Slowbro, but not a Slowpoke.
We can only hope that Slowking will be added soon. Until then, you can still catch a Galarian Slowpoke until June 13, 7 p.m. ET. Who knows if we will soon be able to evolve it into a Slowking? Make sure to head out and capture the time-limited Pokemon.