Planning a 2 week trip to Greece and Turkey from Texas starting in mid to late May of 2025. Current plan is following stops, no order yet.

Istanbul 4 nights
Athens 3 nights
Santorini 3 nights
Chania 5 nights

Love to get some input on best way to travel from spot to spot and maybe order of stops. Appreciate the help in advance.

I would take a day away from Santorini and add it to Athens which has so many more places to visit.
I would fly between your destinations except for Santorini to Chania where you can get a ferry.

For your transportation options, see rome2rio.com and be sure to click through to the underlying sites.

FWIW, I wanted much, much more time in Istanbul, particularly because you'll be jetlagged when you get there. I also wanted much more time in Athens. I don't know what you want to see and experience on this trip, but you might consider skipping Istanbul this time and adding time to Athens. Or Nafplio or Naxos....

You might find some useful information in my trip report on Greece: With Gratitude for a Glorious Solo Month in Greece

Thanks for the input and trip report. I'm assuming Aegean Air is best option there?

IMO, which airline(s) depends on your route. For example: I flew from the US to Crete and from Athens to the US on United, and I took a ferry from Santorini to Naxos. For flights within Greece, I used Olympic.

P.S. I visited Istanbul on a separate trip: Some Observations on a Fantastic Journey through Western Turkey

So on the Santorini to Chania leg all I see is daily ferries to Heraklion and a couple weekly to Rethymno? Nothing that goes directly to Chania, is that correct?

Yes. In May you will have the choice beetween
catamaran from Santorini to Heraklion plus bus from there to Chania
ferry or catamaran to Piraeus plus overnight fery Piraeus - Chania
flight via ATH