Safety leaving luggage in a car at Acrocorinth &/or Nemea

Personally I would not leave luggage in a car visible anywhere. You should have the ability to cover luggage in the truck. I would make sure you bags cut and carry everything else with you.

But maybe I am cautious. I had my car broken into in my town and my bag I left on front seat taken. I never leave anything now.

Thatl's always a reason to rent a sedan or something with a closed compartment for luggage. I remember when 5 of us had an SUV rental in Crete. Our driver cleverly chose parking places where we could back right up to a wall - thus the hinge back couldn't be activated. I;m not familiar with Acrocorinth but have stopped several times at Nemea. It is a very-well keplt up lovely site (guess why: its a site project of UCalBerkeleley$$) and has a well-staffed small museum. I bet if you are worried, you could have your bags stashed in Museum cloakroom. NOTE: It's thrillin if you are going to visit Nemea on the weekend of its every-4-years Revived Nemean Games (June 26-28) which attracts THousands from all ovver world... but those days it would be a ZOO! Otherwise, in May -early ljune it's never been crowded when I visit.

I would use my common sense, I would pack/ load/ park wisely. After all, you are not alone, lots of people rent a car and travel around Greece the way you plan to go. SUVs have a boot top cover if I am not wrong, so potential thief cannot clearly see what's in the boot.

From my personal experience, the places you are inquiring do not attract the same amount of people like Acropolis or other super popular places. So, the potential crime would be lower than other crowded places. Yet, everybody can claim "you never know".

Thank you all for responding. I would have liked to rent a sedan but were a family of 4 traveling (2 adult children in their 20s), so we needed the space.

What makes you think your luggage will be visible?
I don't know any car model in Europe, SUV or not, that doesn't have a top cover hiding the luggage.

When it comes to "SUV" designation with car rental companies in Greece, don't expect the same size car as American SUVs but rather something like a small American crossover type car.

I rented an SUV category vehicle last year in Greece, it was a Ford Puma Hybrid, See below:

https://www.caranddriver.com/ford/puma

So if there is an issue with the car it will be because of its size but certainly not because of the visibility of the luggage

I have received a lot of warning about leaving luggage in the car in Italy (even in the trunk), but I never saw much of a hubbub over Greece. I would have zero qualms at Nemea, as described above--the parking lot is right next to the museum. At ArcoCorinth, just take care where you park and try back in if you can.

I would never leave my luggage in a car when sight seeing. A rental car is incredibly obvious to any thief and they assume that " riches" are inside. In the past, when we couldn't avoid stopping to see a site with luh=ggage in the car we always had one person stay behind and " keep watch". Or.... more commonly we would drive straight to the next hotel and back track to see the site if it was that important. Why take any risk that might create a real nightmare for you.