Hello all,
I have never traveled very much. I'm going to Ireland next September and I've already purchased my ticket, SFO-DUB on AerLingus. I'm going with a group of friends and we all bought our tickets early with AerLingus direct. We live about four hours from SFO and haven't decided about driving down or flying into SFO. If we decide to fly into SFO will we be able to check our baggage through to Dublin when we check in here at home for our flight to SFO or will we have to collect our bags and then re-check them at AerLingus? If we do that how early do you think we would need to arrive at SFO in order to do this and not worry? Thank so much for your help. I'm really a travel rookie!

It will be purely at the discretion of the first airline you use (the flight to SFO.) Most (not all) airlines have "interline baggage" agreements, so they CAN through-tag your bags to Dublin. However, some airlines have a policy of NOT through-tagging bags when the flights are on separate tickets/reservations.

Your best bet is to phone the airline you'd use and ask them what their policy is on through-tagging. You'll probably have to pay their checked bag fee, and you might have to observe their checked bag rules (size, number) which might be more restrictive than Aer Lingus' rules.

If your bags are not through-checked, then you need to leave yourselves <i>a lot of time</i> at SFO to make the switch.

Through tagging works best if the airline you fly to SFO on is a member of the same air alliance as Aer Lingus. I havethe issue you do 4 hours from SFO. If I take Southwest or some commuter flight not within the air alliance I am flying international with, I have to claim back and recheck. If there is a group shuttle may work better as the cost will be split. Cheapest safe parking is now around 11 bucks a day again if group then it can be split making it more do able. So far I have never had to pay bag fee on lst flight if international is in alliance.

Alliance membership has nothing to do with it; besides, Aer Lingus isn't in an alliance any more (used to be in Oneworld, but left 8-9 years ago.)

Most airlines have interline agreements with airlines that aren't partners (e.g. United and American) but generally they apply only if two flights are on the same ticket/PNR.

The Aer Lingus website lists all of the airlines that they have baggage agreements with currently.
You can have two separate tickets.
It would appear that if you drive or transfer bags yourself then they must be checked at least 75 minutes before flight departs. That is when check-in closes.
Keep in mind that if you fly from your home town to SFO you will have to pay to check your bag. The exception is Southwest where bags fly free, but Southwest will not transfer bags to any other airline.

A four hour drive to SFO is not bad. Perhaps you could spend the night in a hotel close to SFO. Many hotels there have park and fly programs. If you spend a night they will let you park your car there for free while you are on your trip. Just google SFO park and fly.

Thanks so much everyone. I sure appreciate your help.

You say you are 4 hours north of SFO . . . whereabouts? Like Siskiyou County - or up the coast somewhere?

Depending on where exactly you are, flying from Medford to SFO could be an option. Much shorter drive and a nice little airport.