Такой транзит возможен и для для граждан стран СНГ, за исключением Украины, Молдавии и Грузии - им нужна транзитная виза для любого транзита через Ирландию.
Цитата из тиматика:
TWOV (Transit Without Visa):
- Passengers transiting through Dublin (DUB) with a confirmed onward ticket for a flight to a third country on the same calendar day. They must stay in the international transit area of the airport and have documents required for the next destination.
- TWOV does not apply to nationals of Afghanistan, Albania, Congo (Dem. Rep.), Cuba, Eritrea, Ethiopia, Georgia, Ghana, Iran, Iraq, Lebanon, Moldova (Rep.), Nigeria, Somalia, Sri Lanka, Ukraine and Zimbabwe.