The tour was supposed to be undertaken by HRH Crown Prince Frederik but he cancelled all official duties for the foreseeable future due to an operation for a slipped disk earlier this month.
Therefore, Mary went solo to the event which celebrated 100 years of diplomatic connections between Denmark and Finland.
The Princess accessorised her outfit - which featured an off-the shoulder top - with chic drop earrings and interesting black pumps with a see-through strip across the toes.
She wore her brunette hair in loose waves around her shoulders and opted for a plum shade of lipstick.
However, the next day, the Princess swapped chic for a rather more geeky look as she visited the Meyer Turku cruise shipyard for a tour.
On Sep. 14, the Princess donned a white hard hat and protective eyewear as she was given a tour by the CEO Jan Meyer.
Mary beamed during the tour – this time opting for pared down barely-there make up.