GAS STATIONS IN IRELAND
Gas stations can be few and far between in rural areas with almost none of them offering 24/7 service. It is a good idea to refill once your tank is half empty. Remember that not all gas stations will take credit cards.
It might sound really basic, but make sure to fill your tank with the right stuff. Whereas at many US gas stations the pump handles for Diesel are green, a green handle denotes unleaded petrol in Ireland. Always read the label. And if you make the mistake of filling up with the wrong fuel: do not start the car, push it to the side and contact your car rental company immediately. They'll put you in contact with a mobile tank-cleaner, which is costly, but way cheaper than losing the engine.
European drivers are obsessed with fuel efficiency. One look at the price of gas in Ireland, let alone in Northern Ireland, will explain this obsession. Expect to pay twice the price you are used to. But fuel efficiency of rental cars should normally be great, even for the larger vehicles, which ultimately makes driving in Ireland not a hugely expensive way of travel.
All grades of petrol, diesel and LPG are available as well as lead replacement petrol (LRP). It is allowed to carry petrol in a can. Credit and debit cards are widely accepted. It's a good idea to let your card issuer know you will be traveling abroad. This ensures they don't suspend your card if they spot it being used in unfamiliar places, which they sometimes do as an anti-fraud measure.