Just another hire car question UK and Ireland

I'm leary about answering questions based on an opinion, but I think not. Here's why: For some reason it had always been in the back of my head that it was against the rules to take a rental car across the Irish Sea in either direction. Physically it's possible since the ferry companies don't give a rip. Cross-channel in not a problem, I do that routinely. From where ever this knowledge came, I believed it so strongly that I once left a car a Holyhead, hopped the ferry, rented another, and then came back to the original one a few days later. The rental insurance structures are different. Credit cards will take care of cdw except for a few countries - - among them Ireland and AUSTRALIA (take that!). Were you to use the same car in both countries, it would seem that you'd have to either be self-insured or pay for the cdw the whole time. Buying cdw effectively doubles the daily rental rate. This question came up a year ago. To formulate an answer, I called the US Hertz Central place and posed the question. I was told that it was, of course, allowed. Since this went directly against what I thought was true, I called the Hertz counter at London City. The supervisor told me that there was absolutely no way it was going to happen and that if someone tried it and had an accident, the entire cost of the damage, car retrieval, etc, would fall on the renter.

For information: The car rental place at Holyhead is at the terminal, at Fishguard it's about half a mile away, I don't know about Cairnryan since I haven't been by there since the ferryport moved up from Stranraer. RyanAir's base rate from Bristol to Dublin is about half the cost of a ferry and takes well less than half the time. The Irish Sea gets real lumpy at certain times of the year.

Taking a car adds about €140 to the roundtrip ferry cost.

Taking a car adds about €140 to the roundtrip ferry cost.

Ed and Jeff Many thanks for the replies. My first thoughts that we would hire in Dublin, return car to Dublin, ferry over to Scotand and pick another car and return to
London. I couldn't locate an agency anywhere near the ferry terminal. I'd assumed a bus ride likely Glasgow, that wouldn't impress my wife after a trip in the ferry. My friends however took a hire car over and back two years ago. but I was wary hence this post. I have also looked at flights over for about €40 each. Regarding insurance, I have $3,500 excess cover with our travel insurance, but based on reading many posts here, I still remain nervous about that. Looking at the various hire companies most make it difficult on their websites to see the real cost. Yes I am sure that's the intent, Europcar do show the additional insurance options as additional items which seems very upfront. Regarding insurance in Australia, I only hire for some of our staff but take the insurance option as our overall fleet insurance includes this. Thanks

I am in the process of planning a trip to the UK next year, and the only restriction I have noticed on rental cars has been taking one to Northern Ireland. The best thing to do is simply to contact the rental rental companies and save their e-mails rather than relying on the advice of us amatures.