You are responsible for paying the tolls. 

How do I pay for tolls in Ireland?

Ten of Ireland’s eleven toll roads have conventional barrier toll plazas. Unless your car has an electronic tag, you will need to stop at the cashier’s booth and pay your toll in cash.

How do I pay for an M50 journey if I’m driving a rental car?

If you intend to travel on the M50 in a rental car, you should contact your car rental company in advance to find out if your rental agreement covers the payment of toll charges. Some companies will include toll charges in your bill; others will require that you pay all toll charges yourself.

If you are required to pay toll charges, you can pay for your M50 journey this way: 

  1. In person with cash or card at any conveniently located retail outlet nationwide that has the Payzone sign.

What happens if I don’t pay for my M50 journey by 8pm the following day?

If you don’t pay for your M50 journey before the next-day payment deadline, you will incur an additional charge of €3.00.