(Story) to Get Slowking – Pokémon (BDSP)
First you need to finish the Pokémon league and register all 150 Pokémon to the Sinnoh Pokedex.
Then you will have to get The National Dex and The PokeRadar from the professor by talking to him in the Sandgem town.
Now we need to go to the fountain spring cave in the underground.
We will find a slowpoke from this location.
You encountered a wild slowpoke!
Push Luxray to catch it.
Slowpoke will be caught!
Next head to the fight area (Get the Boat from Snowpoint city if you have never been before).
Click the Town Map option.
Have a chat with a fisherman here.
Select Yes to obtain the super rod from the fisherman.
Now head to route 225 and fish for a poliwhirl until you get one with a kings rock.
Click the Town Map option.
You are on route 225.
Fish to get poliwhirl Pokémon.
You encountered a wild poliwhirl!
Select No when asked Would you like to give poliwhirl a nickname?
Select See Poliwhirl’s summary when asked Where do you want to send Poliwhirl to?
Select Send to a box when asked Where do you want to send Poliwhirl to?
Select Place the item in your bag when Poliwhirl has a king rock.
Now Give the King's Rock to your slowpoke and trade it for it to evolve into slowking.
Your pokemon is now holding the king’s rock!
Click the Bag option.
Select Trade it when asked what do you want to do with slowpoke? And wait for the other person’s decision.
Sending slowpoke to guru, Good bye, Slowpoke!
And get Growlithe from guru!
Slowpoke’s data will be added to the pokedex!
Congratulations! your slowpoke evolved into slowking! And its data will be added to pokedex!