Flight Booking Site for flying into 1 location and out of another

Always always! book with the actual airlines
Choose “multi-city”
Usually under “advanced search” or something similar

Kayak.com lets you search for "multi-city" routes, and I think others like Google Flights and Skyscanner do also. But I agree that it's best to book directly with the airline you choose, in case any changes happen or problems arise.

If your plan is still flexible, you might consider reversing the order and flying into Venice and back from Rome. The main reason is that the Venice airport is on the mainland and takes awhile to reach from the city itself, which can be a problem with early morning departures. With a daytime arrival, getting to the city isn't difficult. Neither is it difficult to reach Rome's airport for a morning departure (and there's an adjacent Hilton if you're flying very early).

Heed Christine's advice.. book with the airline.

Most here would also suggest flying IN to Venice and OUT from Rome as most US bound flights leave Venice at 0'dark ugly and getting to the Venice airport has unique challenges.

I agree with Christine but if you don't want to go airline by airline (you might not even know which airline flies where) you can use an aggregator like Google Flights, Expedia, skyscanner to actually find the flights then once you see one you like, then go to that airlines website and purchase there. I HAVE found cheaper flights with routes not listed on the airlines website on Expedia and have booked there as long as it is one airline only and had zero problems. Expedia provided their reservation # and the airlines reservation number. I went to the airlines website right away and confirmed my tickets and proceeded to choose my seats.

+1 for using multi-city option on the airline site. You can use something like "google flights" to find prices/airlines/flights that look good to you, but book through the airline site itself.

Do not, do not, get tricked into buying through a 3rd party company. A quick search of the internet and you will find hundreds of posts of problems people have had when something unexpected came up and they had to try to resolve it through a 3rd party instead of the actual airline. If ever there is a time when unexpected things have been occurring regarding travel plans, it is now.

I can't tell where you are flying from, but if you share your preferred city pairs, I bet someone will have had experience with that route and can give you good feedback.

Any of the search engines will have a multi-city option. The jargon "open jaw" was often used by travel agencies to indicate the same things. And it doesn't have to be just two cities. I have strung together as many as five legs. Does get a bit complicated but it works. You should find little difference in pricing between RT trips and multi-city. For me anything less than a hundred dollar difference is "little difference." Nearly all of our European trips are open jaw. And, as mentioned earlier, it is much easier to fly into Venice and home from Rome than the reverse.

All of the above- sorry I was so brief in my response!

I use Google Flights to research, set a few "alerts" then go from there- to the actual airlines website- to book and confirm pricing. I've noticed even Google Flights is not always up to the minute with pricing.
(one flight I am watching now has changed price almost every other day for the past 2 weeks- up then down then up then down lol)

And definitely yes to IN to Venice, OUT of Rome- unless you have good reason to travel in opposite direction.
We've done both- flown into Venice and departed from Venice- it is not impossible, just a bit more complicated. There are direct flights to US from Venice that leave at 11ish- so those are doable with some knowledge about getting to airport.

thank you, all! Super helpful!

OK so this has been mentioned several times with no elaboration - what's the big deal with getting to Venice airport?

If it’s an early am flight and you are staying in Venice proper it usually means getting up in the middle of the night to get to airport in time or staying near airport night before
There are a few transp options- bus/vaporetto combo, water taxi,etc

Bus starts running around 5-5:30 I believe?
Water taxi is about 115 euros.

The airport is a decent distance away.

As I mentioned above if you are flying DIRECT to US on a flight around 11 it is doable. Many flights from Venice to US are not direct- you will change planes somewhere in Europe and those flights leave at the crack of. Allowing 1 hour or so for transpo then 2-3 hours for check in/security means you don't get much sleep the night before!

heather828, if you tell us what your US departure airport is, there might be more help forthcoming.

Sure- we’d be flying out of Newark or JFK.

We fly out of Newark often, mostly actually as they always have better cheaper flights than IAD or PHL

United is the airlines you’ll want from EWR

Thanks for explaining, ChristineH.

And as for EWR, since it is United's hub it is chockful of their planes.