The six-hour presidential inauguration started at 2:15 p.m. when Preca and her husband began to tour their constituency in Maltese cities of Luqa, Siggiewi and Qormi, Xinhua reported.
In Qormi, she was given a grand welcome. Waving Maltese flags, hundreds of people gathered in the town where she grew up, to greet the new president.
At 6:40 p.m., Preca delivered the presidential inauguration address at the palace in Valletta.
Preca, 55, has been serving as Malta's minister for the family and social solidarity since March, 2013. She is the republic's youngest president replacing George Abela, and also the second woman to hold the post after Agatha Barbara who served as the third president of Malta.