Greek Islands in Sept. 2023. Help with picking two.

1) Hydra, close to Athens, car-free, easy to reach, nice beaches, welcoming accommodations

2) Crete, older and different history than the rest of Greece, the most welcoming people, amazing scenery and people. Plan to rent a car, if you want to see more of this large island

I would go to Crete and spend the full two-weeks there.

I would visit Naxos. Definitely an authentic experience with everything you are looking for. We were there for 4 nights but definitely a longer stay is worthwhile, especially since you are looking for some beach time. One option is to stay near St. Georges Beach because you can walk to the beach as well as walk into town, Naxos Town. We rented a car for a day and that was one of the best days of our trip. Visited the Temple of Demeter and villages of Chalki and Apeiranthos. Drove down to the fishing village of Moutsouna on Moutsouna Bay. Had one of the best meals of our trip at Fish Net, a taverna right on the water. And ended our day with ice coffees at the fishing village of Apollonas, another beautiful setting on the water.

So, you could spend a week on Naxos and a week on Crete, as someone else suggested.

Or, a week on Naxos and a week on Paros with a daytrip to Antiparos. I haven't been to Paros or Antiparos, but both places sound wonderful and authentic. You can take the Blue Star Ferry from Naxos to Paros.

I will also go out on a limb and suggest Santorini. I know you say you don't want touristy. Yes, Santorini is touristy for a good reason. The caldera views are stunning! Should be seen at least once IMO. We also rented a car for a day and explored the rest of the island which we loved. Such as the Akrotiri Archaeological site, Akrotiri Lighthouse, Red Sand Beach, and Black Sand Beach at Perissa. There is a lot more to Santorini than the gorgeous caldera views. You could fly into Santorini and stay 3 or 4 nights, and then take the Blue Star Ferry to Naxos, a 2 hour trip.

You could split your island time between Naxos and Amorgos. Two nearby but very different islands.

OR spend the whole time on Crete. We just spent 3 weeks there and barely scratched the surface.

I would also recommend spending 2-3 days in Athens if you’ve never been there.

If you decide to go to Santorini, two nights is enough.
We loved our time on Paros.
Also spent two weeks on Crete, based in Chania, loved it there too.

If you want to avoid the crowds of tourists, I'm sorry to have to contradict some of the other answers, but in the Cyclades islands you will have to avoid Naxos, Mykonos, Paros and Santorini. even in September.

Regarding Mykonos and Santorini, this is nothing new. Naxos has become for a few years the favorite destination of North American travelers (as you will see in all the answers of this forum). Paros is following the same path.

Islands like Amorgos, Sifnos, Tinos, the islands of the small Cyclades like Koufonissia, Folegandros, Kimolos, are still outside of mass tourism. In all these islands you will find what makes the charm of the Greek islands, the beaches, the traditional villages, the blue and white houses, etc. with the authenticity in addition. Crete remains an island where you can also go provided you stay there enough time (at least 5 or 6 nights).

You can combine Amorgos and Astypalea

Combine Tinos with Syros

Entire stay in Lesvos

Entire stay in Chios

Don't overlook the Peloponnese Peninsula which is just as Greek as any island and maybe more so in the more out of the way areas. Filled with history, villages, mountains, beaches and a lot easier to travel in a car than going from one island to another.

Thank you all for taking the time to provide all of these thoughtful recommendations. Question: no one has recommended the Ionian Islands, specifically Kefalonia or Corfu. What are your thoughts on these?

Several reasons you don't see much about Ionic Islands on R Steves forum:
• Most Americans want to see the "calendar pix" type islands (whitewashed "cube" houses, blue shutters) and this style is only in tthe Cycladic Island Group
• It's time-consuming to visit Ionics & afterwards, getting to another island group, could take a full day, maybe involve a flight.

• Some N Americans want to see "history" (ancient ruins, museums etc), and Ionics not as notable for these
• Ionic Group beloved by Brits, Germans etc (popular since Victorian times); some beaches are now purpose-built "resorts" for budget holidaymakers (darts, beer, soccer on TV). That's fine, we need to recognize that for many Europeans, Greece is their Florida... but Americans may seek alternative areas on these isles.

We just returned from a month in Greece, half of that in a rental car. The posting of janet, above, is spot on from what we saw in Kefalonia. We were a week there with our car and loved it. We stayed in Skala and would stay there again, it was a small, lovely, quiet place. This late in the season many restaurants were closed but there were plenty of good places left. It was still warm enough to swim/sunbathe and the beaches were stunning and uncrowded.

Also the Mani peninsula. There is enough there to amaze you for a week. Crete for two weeks, from what I hear.

Santorini should be seen once in your lifetime, add two more days and squeeze it in. While there, we met many people raving about Naxos. Don't neglect Athens if history is your thing. Seems like you need more time with all those interests of yours. ;)

By the way, our entire itinerary was: Athens ~~ Mykonos ~~ Santorini ~~ Athens ~~ Hydra ~~ Ermioni (pick up rental car) —> Nafplio (Mycenae) —> Kardamyli (Mani) —> ~~ Keffalonia ~~ —> Nafpatkos —> Delphi —> Athens (return car)*.

*(~~boat, -->car)