Around 200 cyclists will leave Belfast and travel along the north coast before returning to the city.
Tens of thousands of spectators watched the opening stage around the streets of Belfast on Friday.
Svein Tuft is the overall leader after his team, Orica Greenedge, won the team time-trial.
However, Irish cyclist Dan Martin has been ruled out of the Giro after suffering a suspected broken collarbone in a fall.
Northern Ireland is hosting the initial stages of the race over three days, as 22 teams begin their attempt to win the prestigious title.
In the second stage of the race, the riders will travel through Antrim, Ballymena and Bushmills, before returning to Belfast via Larne and Carrickfergus.
It is expected that thousands of spectators will line the 135-mile (218km) route.
Many roads along the route will be closed throughout the day. Motorists have been warned to expect disruption.
Full details of road closures can be found at: www.trafficwatchni.com/giro.
The third and final stage in Northern Ireland begins in Armagh on Sunday and finishes in Dublin.