A large number of Linköping residents had gathered to receive the princess, who along with mum Crown Princess Victoria and dad Prince Daniel arrived at Linköping Castle at lunchtime.
The royals party began by inspecting the newly decorated salon in the palace which bears Princess Estelle's name.
It was then time for the main attraction to move on and complete the most important task of the day - the inauguration of a fairytale trail which stretches more than 800 metres long fairytale trail which was a gift from the county to commemorate her 2012 christening.
Through the years: Cute pics of Princess Estelle
The trail is described by the county administrative board as an "adventure path with a nature and fairytale theme" and stretches along the edge of lake Tåkern.
While it is far from the first time that Estelle has accompanied her parents on official royal duties, Saturday's outing was extra special because Estelle was herself named as the main participant in the royal calendar.
Born on February 23rd 2012, Princess Estelle carries the title of Duchess of Östergötland and is the first and only child of 36-year-old Victoria and her husband Daniel, 40, who was born a commoner.