Fares come into operation today on the Luas line between St Stephen's Green and Sandyford.
Fares were suspended for the first few days of the operation of Luas, and by last night, over 430,000 passengers had travelled free on the tram system since it started running on Wednesday.
Trams are due to run from 5.30 a.m. today and will run until 12.30 a.m. tonight.
Passengers can get a ticket from a vending machine at the Luas stops. Tickets can also be bought at 13 selected retailers along the route at a reduced rate, a move designed to minimise queuing delays.
Luas fares are to be divided into three zones on the Sandyford line, and four zones on the Tallaght line, which opens in August.
Standard fares within one zone are €1.30, with two zones at €1.60 and three zones reaching the maximum single fare of €2.