There is no Customs when leaving Europe. You would go through Passport Control at the airport where you catch the plane leaving Europe and going to USA.
When taking a flight from Europe to USA, it is usually recommended you get to the airport at least 3 hours before departure.
You will go through US Customs and passport control at your first stop in the US. It depends on where you make your first stop. If you land at JFK when many other flights arrive, 2 hours probably would not be enough. If you are traveling on one airline from Europe to Seattle, they must give you a seat on the next flight if your trans-Atlantic flight is delayed.
Forgot to mention something very important.........check your baggage from Rome to Seattle. When you clear customs, you can take your bag to "Connecting Flights" desk, drop it there, and proceed to your flight to Seattle.
Ok so lets say im looking into a flight that goes from Venice to JFK then to Seattle. I would go through Customs in Venice then? Because im going to Rome/Venice in March for a week. Im flying into Rome and looking into trying to just fly out of Venice to save time. But connecting flight layovers are like all less then 2 hrs so i was curious as to when we have to go through customs. But if my flight from Venice is to New York then i would go through customs in Venice so my 1hr 20 min layover in New york shouldnt be too much of a problem right?
ok. BUT if i flew from venice to rome, then id go through customs in rome? even if i had a layover after rome in New york or Canada?
No, you will go through customs in the first US city you land in. Even if you go through Canada, you will need to clear US Customs. You may have passport checks in Venice/Rome/Canada but customs is for US entry.
On my most recent flight from Milan to JFK to SLC, I had 2 hours to clear customs at JFK and made it with 15 minutes to spare. One time it took nearly an hour to get my bags and then another 45 minutes in line to recheck them. I got to the gate just as they were calling the flight.
Since that time Delta has streamlined the process a bit with more agents. In November, the conveyor was broken and they asked how soon your flight was leaving so get those bags delivered first. If you have to recheck bags there is only one security line after bag check and sometimes it goes very slowly.
No, Venice to Rome is a domestic flight, no customs needed. You will go through US customs and immigration at your FIRST US stop. If you're connecting in NY, you'll do it there, so be sure you leave enough time.
You have to clear both Immigration and Customs at your first stop in the US. So you'll have to collect the bags there and then have them sent on.