As a water polo coach, Ivo Trumbić was an innovator, introducing double training, new methodologies, and video analysis. As a player he was a defender with an excellent shot, who began playing in Split with Jadran and actually started out as a goalkeeper. In 1962 he moved to Mladost, winning three consecutive Champions Cups between 1967 and 1969, a feat still unmatched. Trumbić was a silver medallist at the 1964 Tokyo Games and won a gold medal four years later. He earned 159 caps with the national team.
Trumbić had great success immediately as a coach. In 1971 he won the Greek championship with Olympiakos and in 1976 led the Netherlands to the bronze medal at Montréal. After several seasons at Jug Dubrovnik, Trumbić moved to Italy with the Pescara club where he found the Spanish champion Manuel Estiarte and, in 1987, they won the championship, the European Champions Cup, and the European Super Cup.
After the Italian experience, Trumbić coached the Greek national team and then Patras, AZPC Amersfoort (Netherlands), and finally Rote Erde Hamm (Germany). In 2015 he was inducted into the Watersports Hall of Fame and in 2020, in Croatia, he was awarded the highest sporting honor, the Franjo Bucar Award.