if you do have a ditto on diamond without importing it then post here where and how you got it plz, because i think im in the right spot and im using honey on the grass. so if you also used honey on the grass then post here where you used it and about how many did you use honey on the grass plz

no honey use the poke radar on route 118's grass and eventually you will get one

you cant get a ditto in diamond

You cant find them any where. You have to migrate them to get them.I could trade you one if you want NAME:JEDFRIEND CODE:0344 6422 6636E-mail me your name and friend code if you want to trade and ill meet you onKk cya

Once you have gotten the National Dex off Prof. Oak, he will give you the Poke Radar. Then go to Route 218 and use the Poke Radar. You will not find it right away. It takes time to find a good Pokemon with Poke Radar. Good luck!

You need to use the pokeradar on route 218 to get Ditto to appear, they are however quite rare and it may take a while for one to appear.