PS

we're looking to do a 10 to 12 day trip.

I don't think you should attempt to do all three with 12 days, as it won't be cost effective or relaxing (and flying from point to point and open jaw would be mandatory). However, Italy and Croatia could be doable in that amount of time. There are ferries from Bari and Ancona to Split and Dubrovnik, and and in the north Istria is well connected to Italy by ferry or land.
I always travel in late spring (May), when the crowds are lower but the temps are warm--just barely warm enough to swim in southern Croatia. Fall would also be an excellent time, for the same reasons plus truffle season.

I agree that's a bit much for only 10-12 days, but there are also overnight ferries from Italy to Greece although Aegean Airlines would be much faster (and probably much cheaper).

thanks for the input. if you have to pick only 2 places among the 3 i mentioned, which combination would you guys suggest?

I know that comparing to Canada those 3 countries might seem as dots on the map, but your wording would be more applicable if you were referring on specific towns, not whole countries. It is very difficult to advice as you do not mention a specific area in each country... For example if by "Greece" you refer to Ionian islands such as Corfu, is different than if you refer to Athens or Crete or I do not know what... I think you need to be a bit more specific!

mariha2912---you are so right. i guess what i meant was if you had 12 days and you want to see southern italy and a greece, how would you plan that trip. my wife and i like to eat, walk around, and just kinda hang out to escape a bit.

We did this itinerary before - fly into Rome spend a few days and recover from flight, sight see train to Naples and down to Sorrento/Amalfi coast area to hang out at beaches and eat. sidetrip to Pompeii. We then took a train across to Bari and caught an overnight ferry to Dubrovnik, Croatia. Spent a few days there, took the bus/ferry to Korcula island (we've also done Hvar) where we relaxed and swam a lot and ate great seafood. Then we took the short ferry (couple hours) to Split, spent a day or two and flew out from there back to Seattle (via Zagreb and Frankfurt).

You could also stay more in central Italy and then take ferry over to Istria and do that part of Croatia.

My personal preference is Italy/Croatia over Italy/Greece as it just takes way longer to get to Greece and I get the same vibe and beautiful relaxing water time from S. Dalmatia in Croatia.

You are way short on time.
Rome demands 5 days minimum.
The Amalfi coast another 5.
Sicily really needs 10 days.

You pick it.

It really depends on what you want to see and experience, but I'm one who thinks of these as 3 separate trips. I spent 25 days in southern Italy and felt WAY too rushed. I spent 23 days in Croatia (and another 7 days in nearby locations) and skipped many things I would have enjoyed. I haven't visited Greece yet, but have considered it and haven't come up with an itinerary that would suit my interests in less than 3 weeks. If your goals are "to eat, walk around, and just kinda hang out" I don't think you could lose with any of the three.

Hope that helps!

all the comments are appreciated. certainly a lot to think and consider.

You could combine easily Rome with Athens, and flights are quite cheap if you book in advance...
From Bari you can reach the Island of Corfu, which is beautiful, and then ferry to Mainland Greece and Epirus, one of the nicest regions of Greece ( and completely unknown in this forum, where people only associate Greece with Argolis and 3-4 islands)

You can get to Greece a lot quicker than stefica01 got to Croatia if you fly. Flights from Rome to Athens take only 2 hrs, and a random check on the Aegean Airlines website showed seats in June for only €85 including taxes. For such a short trip I wouldn't even consider ferries, except those within Greece to the islands. Even then, a flight to e.g. Santorini would save a lot of time.

At the risk of sounding like a broken record, 12 days is too short for both Italy and Greece, especially with the long haul flight to get there. If what you want is a visit to two huge cities you could run around, and fly between, Rome and Athens. I definitely wouldn't waste your precious time on long ferry rides. I noticed you mentioned that you are not interested in the historical sightseeing but rather to relax and eat. I would think you'd want to choose either Athens or Rome, then wander off to one or two nearby locations to relax. If Italy - you could head to the coast or up to Florence/Naples. If Greece - you could visit a couple of islands or visit the beautiful Peloponnesus.Of course, it depends upon your style of travel, but I prefer to get a sense of place rather than maximum mileage. Just a thought.

What do you mean by southern Italy? What area?