We will be flying from Philadelphia around 7 PM EDT and getting into Dublin around 6:30AM local time, the next morning (Friday, 9/9). I was planning to pick up a rental car at airport and then drive to meet friends near Galway (Oranmore). I have read someplace that driving any distance - or driving at all - on first day, after the trans-Atlantic flight is not advisable. I have driven in places that follow the British custom of driving on the left before and do not find it difficult to make the adjustment. I normally drive a car with manual transmission and do not anticipate any problem because of the car having manual transmission. Adjusting to the shift lever being on my left should not be a problem for me (the turn signal and windshield wiper levers take more time to get used to). According to tour books, map apps, etc., the drive time is somewhere between 2 1/2 and 3 hours. I cannot see why this is deemed to be a problem, but would appreciate any insight from anyone who has real world actual experience with this. I would also appreciate any insight about travelling to the western coast area on this particular Friday: is there any reason - like a sports event or some festival - to think that traffic would be unusually heavy? We are flying into Dublin, by the way, instead of Shannon, because our plans call for an itinerary that ends in Dublin, making a return flight from there the best option.
We always drive on the first day. It sounds like you are aware of what plays into driving in Ireland and are confident that it won't be an issue. Dublin to Galway is on the major highway so no narrow lanes to begin your journey. With less than a 3 hour drive it seems very doable. We went from Dublin to Glendalough through the mountains immediately after we arrived. Get some sleep on the plane and be prepared to take a break if you get drowsy on the way. Enjoy!
The warnings about driving have to do with jet lag. It would be quite feasible to take a train or bus to Galway, and rent the car after you're caught up on sleep and adjusted to the time zone.
I've done it for a shorter distance but I think it's easier if you're not jet-lagged and have been among left-driving traffic for a few days. Having said that, our plans for a trip at the end of August have us flying from Philadelphia into Shannon and driving the 2.5 hours to Dingle that morning. My issues with left-side driving have mostly been in suburban intersections where instinct takes over and I head for the right hand lane. We'll take it slow and I don't anticipate major issues.
Too late for your trip planning, but I just wanted to mention that renting at Shannon and returning at Dublin only adds about 10 Euros to the cost of the rental (with Hertz, at least).
It'll be Motorway for just about the entire route. Shouldn't be a problem.
I do not sleep on planes at all so the first day is always very hard for me. I would not drive on the first day... even if I were doing so in North America where I am comfortable. If you think you will sleep on the plane an be refreshed in the am, then I think you are fine.
In April we arrived in Dublin mid morning from SFO. Mr. rarely sleeps on the plane and if we are in a country where we will be renting a car, he always drives on the first day as we are not bothered by jet lag on our trips overseas (it's the return that bothers us). He had never driven on the left side; we rented a car with manual transmission. Like Carolyn, we picked up the rental car at the airport and immediately drove to Glendalough through the Wicklow Mountains, about 2 hours with stops for scenery, with no problems. Can't advise about driving towards Galway as we took a different route but it seems you should have no problem adjusting to the difference in the car or the lanes. As to jet lag and sleepiness, which is the main reason travelers are advised not to drive on the first day, only you know how plane travel will affect you. Have a great trip!