I will be meeting my 20 year old granddaughter late October in Greece while she studies abroad. We will have 10 days. Would spend half the time in Greece and the other half in area near. Trying to decide if Istanbul or Dubrovnik and Split is the better second half
It is great to have options that are all good choices. I don't think you can go wrong.
A lot has to do with what you and your Granddaughter's interests are. I've been to all 3, and if I were to choose, I would pick Istanbul. However, my choices aren't necessarily the right choice for you. What are your key interests?
Definitely Istanbul
I’d start by asking her what she’d like to do. Would she be happy island-hopping in Greece with you? You could easily spend the entire 10 days on 2 islands plus Athens.
Or would she rather see Turkey or Croatia? Even though they’re so close, it would take most of 2 travel days to get to & from either country. Any specific must-see sights while you’re there?
And, by the way, where in Greece is she studying? Logistics are very different depending on if she’s on the mainland or an island. If you can give us some more details we’d love to help.