Irish Rail is advising pilgrims travelling to see Pope Francis in Knock on Sunday to book their train seats as soon as possible, as availability is becoming limited.
Seats are still available from Westport, Ballina and Athlone to Claremorris train station, and a shuttle bus will operate from the station to Knock Shrine.
However, passengers travelling from Mayo to the Papal Mass in Phoenix Park are advised that all trains from Mayo to Dublin on Sunday morning are now sold out.
Bus Eireann says there's limited availability remaining on special inter-city services for the visit of Pope Francis this weekend.
Customers are urged to buy tickets online as soon as possible, as bookings will close on Friday afternoon.
Bus Eireann is operating a number of special Expressway Intercity services to and from both Knock and Dublin City on Sunday, to facilitate extra demand.
An extra bus on route 64 leaves Galway at 6am Sunday morning, stopping in Tuam and 6.32 and Ballyhaunis at 7.10am.
An extra service leaves Sligo at 6am Sunday morning, stopping in Tubbercurry at 6.35 and Charlestown at 6.45.
All return services will depart from Knock at 1pm.
Tickets for these buses must be purchased in advance on www.buseireann.ie/popeinireland
For those attending the Papal Mass in Dublin's Phoenix Park, extra buses are operating on Route 22 from Ballina, Swinford and Charlestown, Route 23 from Sligo, Boyle and Carrick-on-Shannon and Route X20 from Galway servicing Loughrea, Ballinasloe and Athlone.
Again customers are advised to buy their tickets as soon as possible.
All return services from Dublin will leave from Busáras at 7pm Sunday evening.