Irish Rail operates a train from Dublin to Cork hourly. Tickets cost $55 - $80 and the journey takes 2 h 35 min. Alternatively, Aircoach operates a bus from Dublin to Cork every 15 minutes. Tickets cost $19 - $27 and the journey takes 3 h. 3 other operators also service this route.
From Heuston Train Station train to Cork Kent Train Station. 2 h 35 min 56€. From Dublin bus to St. Patricks Quay. 3 h 19€. From Dublin drive to Cork. 2 h 32 min 35€. From The 3Arena line 702 bus to Dublin airport, fly to Cork airport, then line 226 bus to Cork. 5 h 55 min 179€.