The main topic of the fifth such meeting will be the future of the European Union, Pahor's office announced in a press release on Friday.
The three presidents will discuss the priorities of the Austrian presidency of the EU, which begins on July 1, and other current issues. Special attention will be paid to strengthening friendly relations between the neighbouring countries.
Also discussed will be the situation in Southeast Europe and the EU membership prospects of the Western Balkan countries, as well as migration.
Among the topics discussed will be marking the 100th anniversary of the end of the First World War.