you have to cheat
you look for it
the answer to this question is to get out of your mums basement, get a job and stop posting questions about Pokemon :D
its a mystery gift and if u dont no u find darkrai there
I think it's the house above the Pokemon center in canalave city but you need the national pokedex and members card to get in
To get into the Harbor Inn in Pokemon Diamond and Pearl. Is when you get to the point you have walked... 999,999,999,999,999,999,999,999,999,999,999,999,999,999,999,999 steps. You go to the house with the sleeping boy inside. Go to Newmoon Island. Find Darkrai. Catch! Hooray. Hope this helped.
Action replay
In harbor inn
In Canalave City above the Pokemon center
In Pokemon Diamond, Pearl and Platinum Darkrai can be found on Newmoon Island. To get to Newmoon Island you need the Member Card for the Harbor Inn at Canalave City.
The membership card opens the door to the Harbor Inn in Canalave City. This is a legendary event cheat in which you catch a level 40 Darkrai.
you get event Pokemon then go cacth creselia and go to canalave city walk to the harbor inn and stay there for a night the you will have a dream you will be on a island and walk up to a puddle and darkrai will be there