4 days in Athens

It depends on what you would be interested in doing and seeing.

With 4 full days you can go to Nafplio, or go to a nearby island such as Aegina. In both cases you can spend a night there.
Or go to Cape Sounion.

Otherwise, even if you have already seen the Acropolis, Athens has enough possibilities to keep you busy for 4 days.
Mount Lycabettus, The National Archaeological Museum, The districts of Keramikos, Psyri, Pangrati, Exarchia, the Flea market of Monastiraki, the municipal market, The Monastery of Kaisariani, the Piraeus marina or the beaches of southern Athens, the Stavros Niarchos Foundation Cultural Center, the Museum of Cycladic Arts, the Benaki Museum, and even the Industrial Gas Museum (!)

If you stay in Athens take a public transport pass, for a few Euros it will allow you to use the metro, trams and buses as much as you want.

We were there the middle of October last year. After two nights in Santorini (which is worth a visit at least one time because it is so beautiful), we rented a car at the airport from Athens Car Rental (ACR) and then drove to Nafplio for three nights. Nafplio is a lovely town with many restaurants, shops, castles to visit and it’s on the water. Several ancient sites are within a couple hours’ drive and worth seeing. We drove to Delphi for one night and saw the ancient sites. Pretty little town. We turned our car back at the airport and took the train into Athens. We took a cooking class in Athens at The Greek Kitchen and had so much fun! I’m going to add cooking classes to every trip now! Also, we took a small group tour to Cape Sounion and Temple of Poseidon at sunset through Getaways Greece. It was very reasonable and we had a really good time!

Hope you have as much fun on your trip as we did!

Check out the area known as Anafiotika on the north side of the Acropolis.

It's like being in a village on Cyclades Island with white washed house with colorful trim and narrow lanes.

Beautiful views of Athens and beyond!

A lot more tranquil for an area so close to the city center.

I agree with the suggestion of going to Nafplio. It's a beautiful small city filled with bougainvillea and located on the water. There are so many ancient ruins you can visit from Nafplio, such as Mystras (my favorite), Epidaurus, Mycenae, and many, many others.

However, there is also a lot to do in Athens as well so you could spend 4 days there. There are many museums and ancient ruins. Did you go to the Acropolis Museum? You could also visit the Athens Central Market, which consists of the fish market and meat market. Very interesting places. And the flea market. There is the changing of the guard at Parliament, and a lovely park near Hadrian's Arch. Wander around the Plaka. I think Athens is a great city!

With 4 days in Athens, you could also take a guided tour to Cape Sounion for a day if you don't want to spend all 4 days in the city. Will you have 4 full days or 3.5 days? How many nights is your stay in Athens? I plan my trips by nights, not days.

If you like to drive around a bit for some sightseeing you could do this.
1) Drive from Athens to Nafplio (+- 1h40) and spend a day there in the town. It's a lovely city.
2) Follow the beautiful road next to the sea from Nafplio till Leonidio, then drive through the countryside till Monemvasia. It's a lovely route and Monemvasia is a hidden gem (takes about 3h30). Explore Monemvasia.
3) Take the ferry to Elafonisos. The ferry is about 1h from Monemvasia. The island has one of the most beautiful beaches (Simos beach and Fragos beach) in Greece. Very lovely if you like to spend a relaxing day in a quiet environment. There is also a little harbour with some cosy restaurants next to the sea.
4) Head back to Athens.