Upvote:1
You do not need a visa to transit airside http://www.inis.gov.ie/en/INIS/Pages/check-irish-visa Information online about connections between the two terminals at Dublin airport is a little confusing, however the Aer Lingus website clearly states that Terminals 1 and 2 are connected both airside and landside https://www.aerlingus.com/travel-information/airport-information/dublin-airport-terminal-2/#/tab-0-map,con
Upvote:2
I was in the same situation: coming in from Abu Dhabi in Terminal 1 and departing to the US from Terminal 2. Both Etihad and the Irish Consulate in San Francisco said that I will need a visitor visa. So I applied and got one (that took about two weeks at Irish Consulate in San Francisco).
However, when I actually reached Ireland, the immigration officer in Terminal 1 said that it was not necessary. That being said, I am not sure whether the airline will allow you to board without the Irish visitor visa.
Regarding going from Terminal 1 to Terminal 2: when you get out of the plane/gate, you will have to go towards Immigration. There are separate lines for EU and non-EU passport holders. Then beyond baggage claim, there is a shortcut to Terminal 2. The officer there led me directly to the security check at Terminal 2, allowing me to completely bypass the long line at Terminal 2 security. Also, FWIW, there is US CBP Preclearance at Terminal 2 which saves you time after landing in the US.