Niinisto, who was reelected for a second term in office two weeks ago, was the last to confirm his visit.
He will join the presidents of Germany, Poland, Ukraine, Latvia, Estonia, Georgia and Iceland, members of the Swedish and Danish royal families, and the presidents of the European Commission and the European Council, who confirmed their plans to visit Lithuania on Feb. 16 earlier.
The guests will attend the traditional ceremony of hoisting the flags of the three Baltic states at Simono Daukanto Square in front of the Presidential Palace in Vilnius at noon on Friday.