Rental Car from Uk to Ireland?
 

We would like to rent a car and drive around England, Scotland and Wales and then take the car over to Ireland by ferry. We plan on being gone 4-5 weeks. Do the rental companies allow this and does the insurance cost more if you take the car on the ferry? I do have a USAA World Mastercard if that makes any difference. Thanks for your assistance.

I wouldn't do it myself. Rent two different cars.

Even if a rental agency allowed a UK-rented car taken over to Ireland (which isn't a given) -- the drop off fees would be Ginormous. Some World Mastercards do cover Ireland rentals -- but most don't. Whether your USAA MC does - you'll have to check. But even if it does -- it might have to be a separate rental contract -another thing to check w/ USAA. And even if all those issues work out, taking a car on the ferry is expensive.

I'd rent one car in the UK and a second one in ireland

It's virtually universal for car hire companies to levy a substantial premium for crossing the Irish Sea. It's almost always the case that flying from Glasgow or Liverpool (or virtually any strip of concrete in Britain) will be a great deal cheaper, even for half a dozen of you, than the ferry fare for a car.

Only you can do the sums in your case.But you'll almost certainly find it cheaper to hire separate cars on either side of the channel, fly between the two islands, dump the second at an Irish intercontinental airport, then either fly home from from there (having bought an open jaw ticket) or fly to a British intercontinental airport and connect to your flight home.