Its near the first island on another 1 i think u have 2 get thenational pokedex
You have to get Pokemon from all the Pokemon games in odurer to get into the pal park in Pokemon pearl
First you have to complete your sinnoh pokedex. Then once you have completed that, go to the beach in the place where Professor Rowan works, and surf right. Soon you will find it. Beware of Pokemon...
right under Sandgem Town and you have to use surf then take a right then you are there