Flight time dublin to san fransico?

That would depend greatly on whether you could find a direct flight or would be subjected to layovers. On average, a transatlantic flight from the pacific coast of USA/Canada to the UK/Europe is 10 hours. Flight times will also vary depending on weather conditions and the top speed of the aircraft you are flying in. Expect to spend 8-12 hours in the air if flying direct from the pacific coast to the UK/Western Europe. A recent flight from Portland Oregon to Amsterdam took 9 hours in the air there, 10 hours in the air back. A previous flight from Vancouver BC to Glasgow UK took 9.5hrs there 12 hrs back