The RMS Leinster Centenary events were officially launched in Dun Laoghaire over the weekend.
A pre-centenary gathering of families and relatives of those who were aboard the boat when it sunk in 1918, was held in the Royal Marine Hotel on Sunday.
Hundreds of relatives and friends of the Mail Boat Leinster passengers gathered to hear details of the planned centenary events, which are set to take place this September and October across Dun Laoghaire and Dublin City.
The mail boat was torpedoed by a German submarine not long after it had left Kingstown (Dun Laoghaire) harbour on its way to Holyhead.
More than 500 people lost their lives in the incident, making it the worst-ever maritime disaster in the Irish Sea. It brought the First World War, in its final stages, very close to Irish shores.
Highlights of the centenary events will include a maritime tribute from Dun Laoghaire Harbour to the site of the Leinster wreck and back, exhibitions of St John Ambulance rescue equipment used 100 years ago and actors in period costume, a tour of Leinster associated graves with an official unveiling of a monument to Leinster hero William Maher and a special mass to be celebrated by Diarmuid Martin, Archbishop of Dublin, in memory of all victims of the Leinster disaster.
An Post will stage a significant display in Dun Laoghaire Post Office will issue a special edition stamp to mark the centenary in October.
The National Maritime Museum in Dun Laoghaire will also hold several events throughout October to coincide with the commemorations.