Portugal/Spain vs Budapest/Vienna/Prague

First a few questions

How much time will you have?

Is it the beginning of September or end of September?

Spain is a big country, what parts are you planning to visit? What parts of Portugal are you planning to visit?

While you can find water in the form of pools, rivers, and lakes, I think you’ll find that seaside will not exist in Budapest/Vienna/Prague.

Look at northern Spain, Basque country, for food, seaside, old town sections, and the occasional museum. Bilbao, San Sebastián/Donostia, Figueroa, Girona, Port Lligat, Barcelona, then catch a cheap flight to Lisbon, and head north from there. This all might involve flying in and out of Madrid or another city, unless you find flights into one place from home and from another to get back home.

Skip Central Europe if you are looking for seaside as you mention. Portugal and Spain have plenty of it. In Spain, for example, we stayed on the Costa Brava in Begur north of Barcelona. I happen to prefer Spain and Portugal to Budapest/Vienna/ Prague and a lot of the reason is that I don’t care much for the food served in Vienna, Budapest, Prague. I got tired of goose and heavy meats very quickly.

We would like to leave at the beginning of Sept. We have 14 days not including travel from NYC. I would check all the most popular locations in both and narrow it down from there. A tour is not out of the question. Everyone raves about Prague, but Portugal and Spain sound as good.

Tough choice. I love Spain and enjoyed the three cities you mentioned. Only because I would have liked more time in Vienna and Budapest, my vote is for the latter. We loved Prague. Either option is a good choice.

I don't know the eastern options as well, but I'll just mention that 14 days is short for almost any version of "Spain & Portugal". With that time you could do a fair visit of Portugal, a very rushed overview of Spain, or a more indepth, relaxed exploration of 2 regions or 2-3 cities within Spain.

They are so different, I can’t imagine how to compare, but I’d say food-wise would be a good point of difference to explore. Plus, comparing three cities to two countries is difficult. For September, I love the northern Spain suggestion, as the south can still be scorching.

We would like to leave at the beginning of Sept. We have 14 days not including travel from NYC. I would check all the most popular locations in both and narrow it down from there. A tour is not out of the question. Everyone raves about Prague, but Portugal and Spain sound as good.

The most popular sites of Spain and Portugal will be dreadfully hot and incredibly touristy in early Sept.

Why not try Poland? It has exactly what you are looking for like good food, seaside and "old towns". With 14 days you can do a nice "Best of Poland" itinerary starting in Gdansk and enjoying the sandy Baltic beaches, then snaking your way south, stopping in Torun, Warsaw, and Krakow, with a nice side trip to Zakopane to see the Carpathian Mountains. Before flying out of Krakow

Plus early September is the perfect time to visit Poland!

Never been to Spain or Portugal so cant answer your question but I can make a suggestion if you choose Budapest / Vienna / Prague.

I a one day light on Budapest for my taste (highly prejudiced) so do some research on each of the three and you might want to balance the time in each a little differently.

The stops in Cesky Krumlov and Gyor are for the "old town" perspective. Sorry can't help with the "seaside" part, but a dang nice river runs through each. Budapest was once ruled by an Admiral if that counts?

If you want to spend more time in the cities, then fly into Prague, then fly to Budapest, then train to Vienna and skip Cesky Krumlov and Gyor.

September

1. Friday
2. Saturday: Depart to Prague
3. Sunday: Arrive Prague mid afternoon
4. Monday: Prague
5. Tuesday: Prague
6. Wednesday: Prague
7. Thursday: Morning Train or Shuttle to Cesky Krumlov
8. Friday: Afternoon Train or Shuttle to Vienna
9. Saturday: Vienna
10. Sunday: Vienna
11. Monday: Vienna
12. Tuesday: Morning train to Gyor (city center and Pannonhalma Archabbey)
13. Wednesday: Afternoon train to Budapest
14. Thursday: Budapest
15. Friday: Budapest
16. Saturday: Budapest
17. Sunday: Home

I don't like the heat, so I would nix Portugal/Spain except for the Basque/Galicia itinerary. Now might be a good time to do that before it gets too touristy.

Budapest to Prague in 14 days would be great. The 3 cities are dissimilar enough to give you a different experience in each. 2 full weeks also allows you to explore each one and include a side trip or two as well.

Poland is also a nice idea - I went to Gdansk (sort of seaside if you venture out of the center), Warsaw and Krakow in 2 weeks. I felt that Warsaw and Krakow were quite similar culturally and I'm not a fan of Polish food, so my vote is for B/V/P.

You can't do Spain and Portugal in two weeks, not even close.
You can do Portugal in two weeks or part of Spain in two weeks.

Iberia is a bit cheaper than central Europe, although Budapest is cheaper.