How do I get into Pal Park I am so confused! PS: I have a National ..

To get to pal park you have to go to route 221 (South of Sandgem Town) Well this was an easy question. I Hoped I helped.

~Twilight_Sasuke~

Okay, go to Sandgem town and have a Pokemon with surf.Go south of Sandgem town and follow the routes of 219,220, then to 221.Keep going east of route 221 and you will find an oranged roofed building.And tada!!!! You found pal park!!!!

You kan go into the palpark if you have in the 2nd lock an other Pokemon game insert

Plug in a pokemon version that's after pokemon ruby and turn on your pokemon diamond. After you got to the menu part, migrate 6 pokemon from your GBA pokemon game then you can go into pal park.

Go to Sandgem Town then go south until you find Route 221. Then you have to go through the Maze.

~~~~~~~~~~~~~~~~THIS PART IS COPIED AND PASTED FROM MARRILAND'S WALKTHROUGH, I TAKE NO CREDIT~~~~~~~~~~~~~~~~

Near the area you enter the Route, by the Swimmer, you can find a Protein on a
Small slice of land. Keep going until you hit the shore. On the shore, you can
Find a Sweet Honey nearby. Again, there are two paths to this Route.

Going north through the grass-filled path will lead you to a house with an old
Man inside. He'll ask to see a Pokemon at a specific Level (it appears to be
Random every day) and your job will be to show him a Pokemon at that Level. I
Have no clue what you get if you do this, but I'd imagine something. To the
West of the house, you can find a Pure Incense.

Back there is just a dead end, though, so return to where you were at and then
Either take the east path or the southeast path to reach the Pal Park. The
Southeast path has more Trainers and tall grass, although it also contains
TM81 (X-Scissor) near the end of it.

Regardless of which way you take, at the end of the Route lies the Pal Park.

Go south of Sandgem Town and follow that route [Route 220] and you'll end up in Route 221. Go to the very end of that, and you'll see a building. That building is Pal Park. Have fun!

So you've seen all the Pokemon in sinnoh? If you havent, you can't get in yet. But by the sounds of it you have. You need other gamecarts to migrate Pokemon to diamond, otherwise palpark is boring.

When you get to pal park if you want to go back there you don't have to swim or walk it is saved to your map so you can fly there.

First go to route 219 go down and then right keep going and enjoy

From Sandgem Town, go straight to Route 220 and keep going until you hit a end of Route 221 which at the end of that route, there should be a building in Pokemon Diamond, Pearl, and Platinum Version are call Pal Park.
To begin a migration, insert Pokemon Ruby, Sapphire, FireRed, and LeafGreen Version into a Nintendo DS' Gameboy Advance Slot then go to menu to find "Migrate from (Gba game here), from there you should go to pal park and start finding your Pokemon over there.
WARNING: THIS DOES NOT WORK IF YOU DO HAVE NINTENDO DSi OR ABOVE SYSTEM BECAUSE IT DOESN'T HAVE GAMEBOY ADVANCE SLOT.