Short side trip from Zagreb to anywhere in central / southern Europe

How about Ljubljana and Lake Bled?

I agree with Bruce. Ljujbljana is a charming city, and there are nice nearby side-trips, including to Lake Bled. Importantly, Ljubljana is not so easy to get to from points west, whereas it's well connected to Zagreb by both train and bus. This is a great opportunity to see it. The city has some interesting museums and a castle.

Definitely not Budapest+Prague in the time you have; total train time would be over 25 hours! Flying to Prague isn't a crazy idea if you can find well-priced non-stops.

Also a "no": driving to Dubrovnik. It's basically a full-day drive.

Another possibility would be to rent a car and head to Istria. Rovinj, Porec, Vrsar, Pula, Motovun, Groznjan are all picturesque towns. Pula has one or two Roman ruins; in the others you're surrounded by old architectures but not a lot of "sights" as such. The countryside in the interior is scenic, too.

Alternatively, target Plitvice Lakes National Park and Zadar, possibly extending to Sibenik or a Split (that would be a rushed visit). You'd want to work your itinerary so you arrive at Plitvice mid-afternoon or later, planning to do the bulk of your walking inside the park first thing the next morning. It is miserably crowded during day-tripping hours and probably worst on weekends when you also may have more than the usual number of Croatian visitors. So you'd head to your southernmost planned stop first, then go to Zadar on Sunday until time to depart for Plitvice. If you go no farther south than Sibenik and get an early start on Saturday, you could probably see that city and drive back up to Zadar to spend Saturday night. One of the monuments along the Zadar waterfront needs to be seen after dark. Hit the park on Monday before heading back to Zagreb.

I think visiting the island of Krk or Rab might also be possible in the time you have, but I'm not sure that's the best plan on a weekend. It might not matter, though.

Plitvice Lakes National Park is beautiful. If I remember correctly, it is about 2 1/2 hr. drive from Zagreb. We actually stayed 2 nights in the park so that we would have 1 full day plus to experience it. Then we continued on to Split and Dubrovnik. Of course, we had more time than you do. Also, it took longer to drive to Split than we had expected. As another poster mentioned, Lake Bled is another option.

Check with your airline, but most request that you check in at least 3 hours before your flight if you are flying transatlantic, which would mean 8am. Assuming that this is the case, then I would recommend that you stay the Monday night in Zagreb.

I agree that you don't have time for Prague given your timescale. You could fly from Zagreb to Dubrovnik for your 2 nights. Alternatively, I would visit Plitvice, Split and nearby Trogir.

Another vote for Ljubljana and Lake Bled. Ljubljana is one of my favorite cities in Europe. (So is Prague - but it is sooooo touristy now.) It's small and charming but not yet that touristy. (In the summer, Bled probably is, though.)

The train is an easy way to get from Zagreb to Ljubljana and back - about 2.5 hours each way and a fairly pretty ride. I guess you could rent a car and drive and try to leave Ljubljana at the crack of dawn to drive back to the Zagreb airport. Having a car in Ljubljana itself isn't necessary, and though it's easy to get to Lake Bled by bus, I recommend having one to take a scenic detour via the town of Skofja Loka. The drive from Skofja Loka to Bled via the mountains, through Jamnik and Kropa, is a lovely scenic drive. Alternately, you could rent a car just for the day in Ljubljana for driving up to/around Lake Bled. Consider a shuttle service like GoOpti to get you back to the Zagreb airport in the morning, but expect to leave super early.

If you choose Plitvice instead (another good choice), consider stay in the town of Samobor on your last night in the Zagreb area - it's just to the west of Zagreb and a cute little town, a departure from big-city Zagreb.

I agree with either Plitvice or Ljubjiana. The point about Slovenia being well connect to Zagreb is a good one. I have found flights into / out of Ljubjiana expensive relative to Zagreb, this could your chance to see it. I would not want to get on a plane if I could do an easy train ride. The flight may be an hour but the before and after means it eats up half a day.

Yeah, I vote for a day trip to Ljub, overnight stay, bus to Plitvice lakes, overnight stay, do the park, back to Zagreb for last night. Zagreb should not be ignored, BTW. It is small but has a lot of fun stuff

We loved Ljubliana and Lake Bled. That's my vote.

The problem you have is backtracking to Zagreb. That wastes a full day, and you only have three to work with.

Can you change your return flight so you can fly out of Dubrovnik or Ljubljana? Don't just automatically say no. Check to see what it would cost if you did. Whatever that is, that would "buy" you a full day (or, expressed another way: you only have 2 days to play with now, you eliminate the backtrack and it extends your usable time by at least 50%, which is worth something). With 3 days, I'd do Plitvice, then head to the coast, maybe Split or Trogir, ending in Dubrovnik, fly back from there. Or, head for Ljubljana and add a day at Lake Bled or in the Julian Alps.

Consider this: for most travelers, I believe the commodity that's most constrained is time. You can always find another hundred bucks, but you probably can't manufacture another day to see Dubrovnik or Lake Bled (without coming back, which may or may not ever happen).

Wow. Thanks for all the great feedback!

It looks like Ljubljana is the clear winner. i will go this route and see if I can start my return flight to the States from LJU instead of ZAG.

If you leave from Ljubljana, do Plitvice Lakes on the way from Zagreb to Ljub.

When in Ljubljana, consider staying in Hostel Celica. It's a converted prison. It's a hoot.

I love Plitvice Lakes National Park, but it's not on the way from Zagreb to Ljubljana. Seeing it when it is other than unbelievably overrun (to the point that your enjoyment is very seriously affected) requires spending the night before your visit at or very near the park. That means you'd be visiting the park on Sunday. There's decent public transportation between Zagreb and Plitvice, so you could probably be back in Zagreb by early evening on Sunday, though I'm not sure how much time would be lost in getting from the park to your hotel/lodgings to pick up stored luggage and then to the bus stop. Whether you could go on from there to Ljubljana that same evening would depend on the precise timing of the bus to Zagreb and the train or bus on to Ljubljana. There may well be less transportation than usual running on Sunday evening.

PL is not that far from the route from Zagreb to Ljub. It's a short trip - 2 1/2 hr s of Zagreb. If they don't want to go, they don't have to. But it is generally speaking on the way.

What time of year? If it's a nice weather time of year, my first choice would be Ljubljana and Lake Bled. Second choice would be Plitvice. They are opposite directions, so I wouldn't do both. If it's not a nice time of year (late October to early spring), I'd skip the outdoor stuff and just spend a weekend in Ljubljana.