President Michael D Higgins is attending a ceremony in Cobh, Co Cork this afternoon marking the Titanic's maiden voyage.
It is 100 years to the day since the Titanic made Cork Harbour its last port of call, with the passengers and mail that went aboard from Cobh, then Queenstown, the last to do so.
The tribute, part of Cobh's Titanic 100 programme of commemorative events, will see a naval fleet review and a flyover from the Irish Air Corps.
The President is due to inspect a naval guard of honour at 2pm, before an ecumenical service at St Colman’s Cathedral concludes with a recital of the cathedral’s 49-bell carillon.
Bonfires will blaze on headlands and islands along the south-west coast this evening to coincide with the actual time the Titanic passed them this day 100 years ago.
The last fire will be lit at 6.12pm on Dursey Island — the last land Titanic passengers would have seen before the disaster.
Thousands of visitors are expected in the Cork Harbour town.
Meanwhile a ship retracing the doomed Titanic’s voyage across the Atlantic was almost struck by tragedy last night after a BBC cameraman developed heart problems and was airlifted to hospital.
The MS Balmoral, which is carrying relatives of Titanic victims among its 1,309 passengers, declared a medical emergency yesterday afternoon, just hours after it departed Cobh.
It was forced to head back towards the Irish coast and sail about 30km east to rendezvous with a coastguard helicopter.
Its crew flew the cameraman to Tralee General Hospital for medical treatment before the ship resumed its voyage to the Titanic wreck site.
The cameraman, Tim Rex, 56, was conscious and stable, and is expected to make a full recovery.