Is it possible to do Spain and Italy in 15 days?

I’m going to assume your dates include travel days. So you really only have 13 nights to work with.

Madrid and Barcelona could (each) easily fill 3 days (4 nights). That leaves you with 4 nights.

You would fly from Spain to Rome, using a good chunk of a day. Rome deserves 4 nights. Then fly home.

To try to get to 5 major cities in 13 nights would require moving almost every other day. Prioritize.

Ok thanks.

Yes that includes travel days.

So you’d suggest just Italy for those two weeks or Spain?

The number of minimum nights needed not including day trips are:
Madrid – three nights
Barcelona – three nights
Rome – four nights that includes Vatican City
Venice – three nights
Florence – three nights

One county fifteen days is short, two countries in that short amount of time and all you will see is the inside of a train/car/bus/plane. Think about Disneyland, would you go for 45 minutes, why bother? The other thing that sicks out to me is all you have listed is large cities. The charm is in the small places, a good trip to me is several small places and one big city. For me no less than 3 night stays, moving takes time that could better be spent enjoying where you are. Love both those countries and October is a good month to travel in either. I prefer Italy in Jan. due to crowds and heat. J

So you’d suggest just Italy for those two weeks or Spain?

Pick one.

Do you have any ancestral connection with either one? If not, a coin toss works and do the 'loser' next time.

Have you looked at each city in enough depth to prioritize what you want to see and do there? If not, one place to start is right here on this RS website.

The Explore Europe section has extensive information on both countries and what to see and do in them. Here are the links:

Italy: https://www.ricksteves.com/europe/italy

Spain: https://www.ricksteves.com/europe/spain

If I'm correct in assuming that this is your first trip to Europe, you'd likely benefit from thoroughly exploring the Travel Tips section. There the basics of trip planning are covered. They are a great way to discover what you need to know that you didn't know you needed to know. Here's the link:
https://www.ricksteves.com/travel-tips

As you get more deeply into your planning, the Travel Forums related to the Travel Tips are under Tips & Trip Reports. Particularly useful categories include topics like Packing, Transportation and Best Walking Shoes for Travel.

I've spent a reasonable amount of time in both countries and I'd choose Italy over Spain. Keep in mind that you need to have 2 nights in a location to have a full day there and all of the cities you list deserve more time than it looks like you've indicated for each of the five of them.

Moving from place to place takes more time than most people expect because you have to pack and check out of one lodging, take transportation to the next one, check in, unpack and settle down every time you go to a different place. You can most efficiently do that if you choose only Spain or Italy. It's such a long way between any of the cities you list in Italy to either of those in Spain that your most efficient way to switch countries would be to fly. If you stay in only one country your most efficient way to move between its cities will be to take the train.

To that point, here's a link to the Man in Seat 61's "Beginner's guide to train travel in Italy": https://www.seat61.com/train-travel-in-italy.htm

And to the same thing for Spain: https://www.seat61.com/train-travel-in-spain.htm

Good luck with your planning.

Looks like a lovely trip! I assume you'll do an open jaw flight plan e.g. fly into Venice, train to Florence & Rome, then fly to Barcelona, train to Madrid and then fly home.

If you look at the RS Best of Venice, Florence & Rome in 10 Days Tour (https://www.ricksteves.com/tours/italy/venice-florence-rome), you get a great template for the Italy portion. Then look at the RS Best of Spain and only look at the activities in Barcelona and Madrid.Wow! Of course you'll have to pare down a bit to make the time fit or extend your trip. (Or you could follow the sage advice on this forum to concentrate just on one country!)

Good luck!

Thank you so much for your help everyone I’m going to do my research today since I don’t have to work

I always plan my trips, but this is my first time planning something like this and it just seems intimidating but this website is a great resource thankfully

I’m trying to tell my wife we should just do Italy and then do Spain later so we can see as much of Italy as possible.

5 major cities in 13 nights would not be fun. You would spend so much time in airports and on trains! Your first day may not be the most useful due to jet lag. People on this forum suggest Venice as a good first location for jet lag. Fly to Venice. Venice two nights(2 1/2 days), train to Florence afternoon of 3rd day(hotels are cheaper in Florence than in Venice). How much time in Florence depends on how much you love Renaissance art. 3 nights would provide 1 1/2 days in Florence-4 nights would be better. You have 7 nights left to split between Rome and one city in Spain that you fly to from Rome and then back from there to the US.

Forget trying to do Spain and Italy in 15 days.

Pick one and go with it.

I have been to all these places, some several times. You could spend a week in Rome and not see all.
Picking one country would involve the travel between the two countries.

Doing Venice (3 days) , Florence (4 days) and Rome (5 days) will take up 12 days. Add the Naples area, staying in Sorrento for three days.

I’m going to skip Madrid and do Barcelona as our base then explore Italy.

Maybe 3-4nights in Barcelona then 10-12 days in Italy.

Since you’re asking for advice, I wouldn’t try to combine Barcelona with Italy - maybe with France. Just as an example, this is what a 15-day trip will give you in Italy. This was my adult daughter’s first time to Europe and my 7th time to Italy. Florence-to-Salerno was 4 hours by train; otherwise, most train rides were around an hour to intentionally maximize her time to enjoy vs. wasted on transportation.

https://community.ricksteves.com/travel-forum/trip-reports/mother-adult-daughter-italy-trip-aug-sept-2022

Or 21 days in Spain, and we didn’t even get to Barcelona:

https://community.ricksteves.com/travel-forum/trip-reports/1st-time-to-spain-trip-report

Even dropping Madrid, you are (in my opinion) still trying to do too much. With only thirteen full days, stick to Italy. Fly into Venice and back from Rome. How you divided the time between them depends on your interest. Personally, I'd spend most of it in Venice (pehaps five days), less in Florence (three days) and five days in Rome. But that's just what I'd do base and having been to all three before.

Ok thanks. We are also thinking of adding another 5-6 days. Might just take three weeks off.

Sure Rick Steves' tours do that much or more than that in 15 days.

Always, always add more time if you can. It spreads the cost of the flights over more days and doesn't have to increase your total expenses that much (if you don't choose high-end hotels). No matter how short or long the trip, you have a bunch of wasted travel time at the beginning and end; that doesn't increase if the trip is longer.

The more research you do, the more things you'll uncover that sound intriguing, not to mention the special events and exhibitions you may learn about after you hit a city.

Glad you can add another 5-6 days. That will make a huge difference!

...thinking of adding another 5-6 days...

That puts everything in a whole different light. Suggest you lay out a basic itenerary based on total nights, and then come back to see if it needs to be finely tuned.

This sounds like a serious case of FOMO (fear of missing out). By doing a blitz trip like this, you will be very tired.

In addition, every time you switch cities, you lose most of that travel day. So you do not have 15 days, you would have 15 - 5 or 10 days. The first and last days are a loss as well - arrival you are jet-lagged, leaving you will have to get to the airport.

Last Sept, we spent 22 nights in Italy. We went to Florence, Milan, Turin, and 4 small cities. We did not go to Rome or Venice. We took trains between cities, and the longest time on a train was 4 hours. Most were 2 hours.