If you run out of credit while travelling, you need to top-up before you can use your card again.
You can use your card to travel if your card is in a positive balance, even if the balance does not cover the full fare. Your card will then go into a negative balance and will not work for subsequent journeys until topped up.
Eg: Balance €1.00
Card will go into negative balance of -€0.40
Card will not work until topped up.
Card topped up by €5.00
Balance €4.60 (€5.00 minus negative balance of €0.40)
To see where you can top-up your TFI Leap Card, click here.