Go talk to the worker inside the pal park after talking to prof. oak who's going to Eterna city. Then, say yes if he asks you to join the catching show.
P.S.: You can only join if you migrate Pokemon from the Pokemon GBA games.
Chat with our AI personalities
by migrating pokemon from your gba game
The Pokemon in there is a Legendary Pokemon named Azelf. So good luck catching her/him. -Camille
You have to migrate Pokemon from older games like Leaf green and Fire red. Then get them to your game. You will be able to enter the catching show. You can enter any Pokemon from the game you got Pokemon from.
Pokemon diamond & pearl
To catch every Pokemon, you need action replay for the few last diamond legendaries. You will need Pokemon fire red/leaf green and emerald. Migrate them to Pokemon diamond. In Pokemon diamond, fill up your pokedex by catching Pokemon normally or with poke radar, or use gts. It will take a long time to catch all Pokemon