A contingent of more than 450 people from Scouting Ireland is attending celebrations at Brownsea Island in Dorset marking the 100th anniversary of the creation of the movement.
Scouts from around the world have set up a symbolic camp on the site of the first ever such gathering.
Two scouts from each of 155 countries attended a Sunrise Ceremony on Brownsea Island, where British army officer Robert Baden-Powell launched the organisation in 1907.
Over the last century scouting has grown into an international movement whose members have included US President George W Bush, former British Prime Minister Tony Blair and former French President Jacques Chirac.
Today's ceremonies come as scouts are gathered in Britain for the 21st World Scout Jamboree, which takes place every four years. This year's 12-day festival runs until 8 August.
The first Scout jamboree was held in 1920, when some 8,000 scouts from 33 countries gathered near London.
This year the movement is returning to its roots for the centenary, after jamborees in South Korea in 1991, the Netherlands in 1995, Chile in 1998-99 and Sattahip in Thailand in December 2002 and January 2003.
According to the World Scouting Organization, some 500m people have sworn their oath to the movement.
Officials admit that the movement has waned somewhat in rich countries in recent years, but insist its future is bright.
The jamboree got off to a royal start at the weekend with Britain's Prince William in attendance as 40,000 people from across the globe gathered near Chelmsford, northeast of London.
