How do you catch a dido without a poke radar in diamond?

Answer 1

"Dido?" Don't you mean "ditto?"

To catch a Ditto, go to Route 218 and use the PokeRadar.

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man you're super DUMB!, then question was how without!!

If you have the national pokedex:

Fly to hearthome city, then go down towards pastoria, on the way you'll see a mansion. Save first then walk into the mansion and talk to the owner, he'll say 'I woke up this morning and i saw a cute eyed _____' If he says ditto then you go into the trophy garden and find it (it may take a while), if he doesnt say it turn off your Nintendo and repeat it until he does

Hope I helped better than that dummy!