The premier will start her eight-day official visit to the Eurpean countries with Switzerland. She is scheduled to attend the 24th regular session of the United Nations Human Rights Council in Geneva where she will deliver Thailand's stance on dealing with human rights violations including human trafficking and the protection of children and women.
Italy is her second destination. This will be the first official visit to the republic by a Thai prime minister in nine years. The two countries have had close relations since the establishment of diplomatic ties 145 years ago.
Ms Yingluck will meet with her Italian counterpart Mario Monti. The leaders will discuss promotion of the jewellery trade and the design industry, as well as the rubber market. Thailand is the world's leading producer of natural rubber.
The Thai premier aims to invite Italian investors to the kingdom. She is accompanied by representatives of 56 Thai companies seeking business there.
In Vatican City, Ms Yingluck will pay respects to the leader of the Roman Catholic faith. The meeting will be the second visit to the Vatican by a Thai leader, the first 58 years ago by Field Marshal Plaek Phibunsongkhram.
Ms Yingluck will visit Montenegro next Friday and Saturday, where she will become the first Thai prime minister to visit the country.
Thailand intends to boost relations with Montenegro and seeks to open trade and investment opportunities with the Balkan country.
Ms Yingluck will also witness the signing ceremony of an agreement on visa exemptions for Thai and Montenegrin diplomats and state officials, paving the way for further cooperation in other sectors.
The premier denied any personal conflict of interest on her visit to Montenegro, defending her visit by explaining that Montenegro is a high income country and that business cooperation and tourism is high on her agenda for this trip.