Over 75 people have set off on a 340km cycle from Dublin to Blacksod, to honour the memory of the four Coast Guard crew members who died off the Mayo coast last year.
The event takes place just days before the first anniversary of the Rescue 116 tragedy.
The bodies of Dara Fitzpatrick and Mark Duffy were recovered in the days following the fatal helicopter crash.
Two other crew members, Ciarán Smith and Paul Ormsby, remain lost at sea.
Members of the Ballyglass Coast Guard unit said they are undertaking the journey to remember all those who have lost their lives off the coast.
Welcome sustenance at Ferricks Hotel Rathowen, 2 legs down,1 to go 60K to Carrick on Shannon, no casualties thank God, ready for the off #milesintheirmemory #R116 @patmcgrath @rtenews @radiomidwest pic.twitter.com/gKx3sHfBtk— Keith Swanick (@DrKeithSwanick) March 10, 2018
They set off from the R116 base at Dublin Airport this morning and will travel as far as Carrick-On-Shannon today, before completing the journey to Blacksod tomorrow.