So first of all the flat is great and really well located (30 minutes away from Acropolis, 15 from the national park, and 7 from the metro).
But the best is Denia! She is really helpful and does the extra mile in terms of recommendations, transports and what not. So thanks again, and hope to be back soon!
The apartment is located outside of the city center of Pireaus. I would call it the perfect location because it's so quiet but at the same time you need only 20 minutes by walk to Piraeus Port or 10 minutes by bus. Bus station, supermarkets, cafes,.. have a walking distance of 5 minutes, so even you are not in the center you have everything very close. For children there are also some playing grounds nearby.
The apartment itself is very beautiful and comfortable, everything is clean and in a good condition. All in all we enjoyed our stay. The owmer is very friendly!
I experienced already that all apartments in Piraeus heat with solar energy so you need to have patience to get warm water. Maybe also because the house is very old. With a child I didn't like the fact that sometimes there was only cold water.
A very big plus is the flat TV and the strong wifi connection.