King's Rock allows you to get your hands on Politoed and Slowking, two Gen 2 evolutions.
That, in turn, means new methods for evolution: the King's Rock was used for evolving Poliwhirl and Slowpoke in the main Pokémon games by having them hold the item when being traded - a mechanic that's not in Pokémon Go at all as things stand.
So with that in mind, how do you evolve Poliwhirl into Politoed, and evolve Slowpoke into Slowking, and likewise how do you get the King's Rock in Pokémon Go?
On this page:
How to get King's Rock in Pokémon Go
King's Rock in Pokémon Go is found in much the same way as several other special evolution items - as a rare drop from PokéStops, and has a chance of being rewarded on the seventh day of your PokéStop Daily Bonus streak.
There's no guaranteeing which evolution item you'll get, but with only a handful in the game, at least you hopefully shouldn't have to wait too long to get a hold of all the items you need.
If you are playing during the A Very Slow Discovery event in June 2021, know you can get a King's Rock as part of the 'Evolve a Pokémon' research task, and one for free from the weekly Event Box in the shop.
How to evolve Poliwhirl into Politoed in Pokémon Go
Poliwhirl, in the main Pokémon series of games, evolves into Politoed in a little more long-winded manner than in Pokémon Go. The original method involves not only finding and using the King's Rock, but getting yourself a trading partner, so that Poliwhirl can hold it and be traded in order to evolve.
Here in Pokémon Go, it's far easier: simply find yourself a King's Rock and use both that, and some Candy like usual, to evolve it into Politoed from the same in-game menu you'd use to evolve a Pokémon normally.
- Poliwhirl to Politoed Evolution cost - 1 King's Rock and 100 Poliwag Candy.
How to evolve Slowpoke into Slowking in Pokémon Go
Evolving Slowpoke into Slowking works in much the same way as evolving your Poliwhirl into a Politoed.
Like the evolution chain above, Slowking comes as a branching evolution from Slowpoke, acting as an alternative to Slowbro. Interestingly, as you'll see in our best Pokémon in Pokémon Go listings, both Slowbro and Slowking have identical stats, meaning the choice to evolve for one or the other is purely down to your personal preference - and for completing your Pokédex, of course.
Again, as above, to evolve your Slowpoke into a Slowking simply use your stored up Candy, and a King's Rock, to evolve it via the usual in-game menus.
- Slowpoke to Slowking Evolution cost - 1 King's Rock and 50 Slowpoke Candy.