Josip Costaperaria studied architecture at the Academy of Fine Arts in Vienna at Otto Wagner studio (1899/1900). He didn't finished his study under Wagner's mentor ship but only in 1927 with prof. Clemens Holzmeister at the Akademie der bildenden Kunst in Vienna. In the Austro-Hungarian monarchy period he lived in Trieste with Slovenian concert singer Mira Dev. He collaborated with Maks Fabiani on the project for the Narodni dom - Hotel Balkan in Trieste. After World War II he designed Ljubljana Fair Congress (1921), Ljubljana Palace (1923-1925), the house Suklje (1928), the house Dular (1930) and housing Sahovnica - Checkerboard on Vrtaca (1931-1933). He was the architect of Senator and former Ljubljana mayor Ivan Hribar and a member of the Rotary Club Ljubljana. He was one of the Petkovec - in modernism oriented group of architects, which were the opposition to Plecnik. After the Second World War was accused to be involved in the Fiera di Lubiana (1941) which was organized during the Italian occupation. He died alone and in the absence in Ljubljana.