Croatia and Greece 2 weeks?

You’ll need at least 10 days for the highlights of Croatia and could easily use two weeks there.

If you want to add Athens, Santorini and Mykonos, you’ll need to add time for an optimal trip.

In April you will not be really enjoying the beach much--seas are absolutely frigid. I would adjust to more of a town and city kind of trip.
I don't recommend these two countries in two weeks either--too much hopscotching and skipping over too much.

This is definitely possible! You could do a week in each. In Croatia, I would decide whether you want to see more of the north or the coast/south/islands and select 2-3 destinations. For Greece in one week I personally would visit Athens and one island. April will be a bit too cold for the beach still so you can take that into account with your planning.

What do you consider the highlights of Croatia? Are you okay with it being too cold for beach?
I see no direct flights from Zagreb or Split to Athens in April (at least according to Google, perhaps there are some seasonal flights). There are direct flights from Dubrovnik to Athens, so you could fly into ZAG and from DBV to ATH, home from there. But I still think you lose too much time in transit for this to be viable.

With "two weeks" I would suggest you pick EITHER Croatia or Greece. One or the other, not both. These should really be two separate trips – and each country deserves a lot more time than you would have in your proposal.

Visiting Greek islands eats up days by the handful just getting around. Croatia and Greece are not very well connected.

Also, you should define exactly what you mean by "two weeks." Is that two weeks from when you lock your front door at home, until you get back home? (That would mean your trip would only have about 11 or 12 full days on the ground in Europe.) Look at exactly (and specifically) how many days and nights you have to spend in Europe, on the ground, not including your arrival or departure days. Do the math, I think you will find you will want to stick to either Croatia (can be done pretty well in 11-12 days) or Greece (surprisingly hard to do in 11-12 days when you toss in a handful of islands), not both.

I am going to be the odd man out here again. Visiting Athens, Mykonos, Santorini and highlights or Croatia in a couple weeks sounds like a great trip. (So does spending two weeks in Greece or two weeks in Croatia!)

Heck, I'd be tempted to add a stop in Slovenia!

Pacing is a personal choice. I like the tempo recommended by Rick Steves-- see his country recommended Itineraries. This forum seems to be dominated by excellent, thoughtful, well-travelled folks who recommend slower speeds. Unless I was on a beach-y vacation-y mood, a day is all I can take of Santorini and Mykonos-- and two days is more than I personally need in Athens.

Whatever you choose, I'm sure you'll have a great time.

Happy travels!

This is just the beginning of the conversation, hopefully. We've provided our initial thoughts, now hopefully the OP will come back to discuss specifics and cobble together a great trip regardless.

I agree that it is certainly possible to spend a week in Croatia and a week in Greece. Just remember that you will only get a small taste of each country. And you will be doing a lot of traveling around, which will take up a lot of your time.

What do you consider are the highlights of Croatia? Dubrovnik, Split, an island such as Hvar, Plitvice Lakes NP?

If you do visit both countries, I recommend spending time in Athens and one island. I know that many people don't like Santorini because of the crowds, etc. but we thought it was stunning! And Santorini doesn't just consist of the caldera views, which are gorgeous, but I would recommend renting a car for a day and visiting the Akrotiri archaeological site, the black sand beach, red sand beach, and one of the smaller villages.

Personally, I would consider visiting both countries in only 2 weeks very frustrating.

So, if this were my trip, and it's not, I would spend all 2 weeks in one country, not two. This will give you time to see more sights, cities, villages, and countryside in that country. With 2 weeks in Greece, you could have a combination of 1 or 2 islands, the Peloponnese Peninsula (such as Nafplio), and Athens. In Croatia, you could visit Dubrovnik, Split, an island such as Hvar, Plitvice Lakes NP and Zagreb. Maybe do a day trip to the Bay of Kotor in Montenegro from Dubrovnik. Two weeks in one country will be more relaxing.

As to which country? Both are amazing, interesting, and beautiful. What are your interests?

There are no travel rules and no can's or can nots. About 4 years ago I took my daughter to Greece for a week, then Croatia for a week. Great trip. It was a return to both for me, but a first for her and she loved it. It being April I might be inclined to do a tour from Split to south of Dubrovnik. That would be a great 7 days including travel to Europe, then make Greece 9 days including the trip home (2 weeks + the following weekend = 16 days).

With 2 weeks in Greece, you could have a combination of 1 or 2
islands, the Peloponnese Peninsula (such as Nafplio), and Athens.
kmkwoo is correct. With one week you will only see 5% of the top 100 sites but with 2 weeks you will see 10%! So, who gets to decide where to draw the line? You do. Lots of luck with that.

And now I hope my opinion doesn’t offend. Not meant to. But I have been dragged back to Croatia three times. Once with my S.O., once with my daughter and once with my other S.O. (just two months ago) and that doesn’t count one additional trip where I just spent 2 nights i Dubrovnik on my way to one of my favorite countries: Montenegro. So, I love Croatia, don’t I? No, Croatia never spoke to me, other than Dubrovnik and Cavtat, a rather interesting winery and a rather interesting olive plantation there isn’t much I want to return for. And now that prices have gone up 50% in 3 years ..... well ….. When you get Croatia advice, you might ask exactly where they went and for exactly how long and how long ago was the trip; because this is a country that has experienced tremendous change in travel atmosphere over the last decade and things change.

So, my suggestion is more time in Greece. Well, I am an architect, and I do love the classics. I read most of them and I made my poor kids read most of them. How one region could produce so much brilliance over such a short period of time ... especially given the relatively small population ... its freeking amazing. HOWEVER, after a few trips I exhausted my explorations along those lines and never got comfortable in the country other than for academics. But it is absolutely a place everyone should see and experience.

Having said all of that, different places speak to different people in different ways. You could fall I love with both, and I would be jealous if you did. In April, I would probably go to Bosnia & Herzegovina if I needed a second stop. Heck, there’s an idea. I know you didn’t ask, so forgive me.

1 depart the US
2 Arrive Sarajevo
3 Sarajevo
4 Sarajevo Blagaj Tekija to Mostar
If you wanted more time in Greece, you could make Mostar a stop on the way to Dubrovnik and not spend the night. It’s roughly 3 hours to Mostar than 3 more to Dubrovnik but lots of little villages along the way, eat lunch in Mostar. It would be a 10 hour day, but a fascinating day.
5 Mostar to Dubrovnik after lunch
6 Dubrovnik
7 Dubrovnik and surrounding
8 Fly to Athens
8 – 16 in Greece