The DART will not run between Grand Canal Dock and Bray over Easter weekend, Iarnród Éireann has said.
There will be no services between the two stations from Saturday and Easter Monday.
Iarnród Éireann said the the suspension is due to a series of works that include overhead line renewal, track renewal and train protection system works between Grand Canal Dock and Bray.
It said Dublin Bus and Go Ahead will accept rail tickets on relevant services.
Irish Rail is also advising customers that many services will run on a Saturday timetable tomorrow, Good Friday.
The works will also affect the Rosslare Europort Intercity line and Iarnród Éireann said there will be bus transfers between Dublin Connolly and Greystones.
Separately, due to works on the Belfast Grand Central Station project, there will be no services between Portadown and Belfast.
Iarnród Éireann said: "Customers on the Dublin to Belfast Enterprise services can avail of bus transfers between Newry and Belfast for travel to/from Belfast."
