Originally Posted by
YVR Cockroach
You used to clear US immigration at DUB but not customs. Customs clearance came when you arrived in the US. I understand its both now so maybe that's changed.
You are correct. This applies to both Shannon and Dublin Airports, so when you arrive in the USA in UA (CO) you arrive as a domestic flight into EWR. It is great as you do not have to go through TSA abuse if you are connecting. Irish security is way more professional than the TSA.