Best air route--going to London and Ireland

You might want to consider flying "open jaw" into one airport and out of another. Having flown home out of both Heathrow and Dublin airports, I would fly out of Dublin every time. It can take hours and hours to get through security, etc when leaving out of Heathrow.....flying out of Dublin was a breeze. The other advantage of flying open jaw is that you'll only make one crossing between England and Ireland, rather than two. If you are traveling from Ireland to London via ferry and train, it will take the better part of a day (although it can be an enjoyable trip). I have heard it is faster to fly between cities, but you still have to get to the airport X hours early, get through security, hope there are no delays, and get from the airport to your next destination. Why do this twice if you don't have to.

Ditto what Ruth says regarding flying open jaw. When you research don't look for one way tickets, use the multi city option. For example mine might be LAX to SNN (LA to Shannon), LHR to LAX (London Heathrow to LA). One ticket.
Then take a puddle jumper across the sea to London. RyanAir most likely.

We have used Aer Lingus for the hop over to Dub and back from Heathrow. No problems for us in London, with a 2 hour headstart for an early flight, and Dub was real easy...before Terminal 2 existed. We didn't have the "Open Jaw" option, since we had free cc rewards tickets. Also may want to look into Flybe...they don't seem to get so many negative reviews like Ryanair D.

Thanks to all for the good leads; I flew in and out of Dublin in March and I DO NOT like the new Terminal 2!!Long waits, long walks; not as much fun at the airport leaving Ireland as it was not too many years ago, esp from Shannon!

You can fly into Heathrow, then to Shannon, pick up a car there for your travels in Ireland and drop the car in Dublin and fly home, or vice versa.