2026 May or September timeframe in Greece don’t know where to go

Two places that might meet your requirements would be Athens and the island of Naxos, two very different places, obviously. Athens will give you many choices for historical sites and museums, great restaurants and shopping. From Athens, your nephew and his girlfriend/wife could go to Nafplion on the Peloponnese Peninsula for a couple of nights if they wish, or perhaps Delphi.

Naxos, of course, will give you beach time, some hiking, visiting mountain towns and fishing villages, and shopping and great restaurants in Naxos Old Town. Naxos is a great place to spend a week.

I also recommend that you purchase some good guidebooks, such as Michelin Green Guide, Rough Guides, and Rick's book. I used to really like Lonely Planet, but I don't care for their new format.

Based on personal experiences, in 2018 and 2019, when my husband was your ages, we visited Athens plus the Peloponnese peninsula (April 2018) and the island of Crete (Sept 2019). If April is close enough to May, I hope these are comparable.

All these have beach access, amazing historical sights, fantastic food, and shopping/activities, too. We had a rental car both trips, and stayed in several places, but you could keep it to one or two.

Athens, the capital, of course, a key destination. But on the Peloponnese, a great base would be Nafplio. Instead of Athens, if you wanted to be closer to Delphi, consider basing in Galaxidi.

As for Crete, there are several locations - some much busier in September (read: crowded) than others. If beach time was a priority, but access to an ancient Minoan archaeological site was, too, We enjoyed Pitsidia, in the south. The capital city on Crete, Iraklio (aka Heraklion) also was a good visit. Another option is Hania (aka Chania), a port under the Venetian Empire.

Naxos and Crete are our favourite islands so I have to agree with the first two posts for your island choice.
Crete is very large and a week there will not be sufficient time to do a lot of exploring.

Many experienced travellers to Greece suggest you get out to your first island on day of arrival. Its better to get over Jet lag on an island where the pace will be slower. I would suggest you look at Naxos. It has an airport so its easy to get to on day of arrival. Consider looking for accommodation at St George beach area which is a short 10 minute stroll along the headland into Naxos town. Its a good sand beach and has hotels and guest houses in the area. Naxos has mountains and mountain villages to visit, good beaches and a lovely main town (Chora) with the harbour and a maze of back alleys leading up to the Venetian era Kastro at the top.

I also think the recommendation to do Nafplio on the mainland is a great idea. Its a delightful city right on the sea so it feels like an island. It has a lovely old town also from the Venetian era. Its a two hour commute from Athens and has several ancient sites in the surrounding area.

You are going to have to get back to Athens for your return flight. I would suggest you take a couple of days off of Nafplio and Naxos and spend the last 2 or 3 nights in Athens. Its well worth the time with so many antiquities.

This is what I am recommending.
Naxos 2022. https://www.flickr.com/photos/stanbr54/albums/72177720299940917/

Naxos town 2024 https://www.flickr.com/photos/stanbr54/albums/72177720318203165/

Nafplio https://www.flickr.com/photos/stanbr54/albums/72157632094108982
Nafplio 2024 https://www.flickr.com/photos/stanbr54/albums/72177720319228274

Thank you all three of you gave amazing information to help me delve deeper into specific cities. I’m so excited yeah it is very far away. We are in the midst of planning our trip to Rome, Germany, this September.!

I cannot find a St. George Beach area in NAXOS?

Agios Georgios beach. Translated to English is Saint George beach.

Jette, we stayed at Hotel Palatia while in Naxos. It's located on the edge of Agios Georgios. A great location. About a 10-minute walk to the Chora (the Old Town).

I also agree with the recommendation to spend a week in Nafplion. It's beautiful, and it's exactly as stanbr describes. From Nafplion, you can visit many antiquities, such as Epidaurus, Mycenae, and the gorgeous Mystras (Byzantine ruins). Mystras is my favorite! It's about 1.5 hour drive from Nafplion but well worth it. We visited as a daytrip from Nafplion. And there are many other antiquities/ruins as well.

I haven't been to Crete yet which is why I didn't recommend it since I don't have firsthand knowledge. We do have friends who love Crete, and they have been visiting for years. I do hope to get there one of these days!

StanBR and KRKwoo thank you!