Prezelj received the Golden Order for Services for his "legendary achievements in alpine climbing and for the promotion of Slovenia in the world".
He is the only alpine climber in the world to have received four times the most prestigious global award for mountaineering, The Golden Ice Axe, the president's office said.
In his more-than-twenty-year career, Prezelj climbed over 2,500 peaks in the Himalayas, Europe, Alaska, Canada and South America, often picking routes never climbed before.
Brvar, the head of the Alpine Association of Slovenia between 1990 and 2001, was honoured with the Order for Services for his long-term volunteering work at the association and his "extraordinary contribution to the forming of the national sports policy".
Alpine and sports climbing instructor and guide Česen was handed the Medal for Services for his "versatile contribution to the development of sports climbing and his top mountaineering achievements".
Pollak, an expert, instructor, analyst and author of several books on mountaineering, received the Medal for Services for his contribution to the development of volunteer mountain guiding, lifetime work at the Alpine Association and his contribution to the development of the Slovenian mountaineering school in Nepal.
Mountaineering is one of the most popular pastimes in Slovenia, while the country's top mountaineers are widely recognised as belonging among the best in the world, with their achievements outnumbering those of much larger nations.
At one point, Italy's Reinhold Messner credited Slovenians with eight of the 32 biggest achievements in the Himalayas, followed by the Polish with five.
Along with Prezelj, the Golden Ice Axe has also gone to Andrej Štremfelj, to the late Tomaž Humar and Vanja Furlan, to Boris Lorenčič and to the late Pavle Kozjek.