Zlatko Šimenc, a revered figure in Croatian and Yugoslav sports, passed away on March 17, 2026, in Zagreb at the age of 87, after a long and severe illness. A distinguished water polo player, coach, and kinesiologist, Šimenc was unique for his exceptional career as a dual international representative in both water polo and handball, leaving an indelible mark on both disciplines. His passing prompted widespread tributes, with the Croatian Water Polo Federation (HVS) publishing an 'IN MEMORIAM' and Gordan Jandroković, President of the Croatian Parliament, sending condolences, recognizing Šimenc as an "incredible example of sporting excellence" and an "exceptional man". HAVK Mladost expressed deep sadness, and the Zagreb City Sports Association (Sportski savez Grada Zagreba) mourned him as a "legend of Zagreb sports".

Born in Zagreb on November 29, 1938, Šimenc was the youngest of four children to parents who had moved from Slovenia to Zagreb for work; his father was employed at the Penkala factory and later ran a fruit and vegetable kiosk. He began his sporting journey in swimming at the age of 11 in 1950. He transitioned to water polo in 1955, joining the legendary HAVK Mladost club, where he would spend his entire playing career. During the winter months, he also excelled in handball, a testament to his remarkable athletic versatility. Known affectionately by his nickname 'Ćos', Šimenc initially enrolled to study law in 1958 before switching to the newly established Institute of Physical Education in Zagreb in 1959.

Šimenc's international career saw him represent Yugoslavia with distinction in both sports. He played 101 matches for the national water polo team between 1957 and 1967, participating in two Olympic Games, placing fourth in Rome in 1960 and winning a silver medal at the 1964 Tokyo Olympic Games. He also secured multiple medals at European Championships, including silver in 1958 and 1962, and bronze in 1966. Further water polo accolades include a gold medal at the Mediterranean Games in Beirut in 1959 and a silver medal in Naples in 1963, as well as a gold medal at the Universiade in Turin in 1959. In water polo, he primarily played as a defender, occasionally at center, focusing on building play and assisting.

His prowess extended to handball, where he played 24 matches for the national team from 1957 to 1961, participating in two World Championships in 1958 and 1961. In handball, he was known as a goal-scorer, and former teammate Ozren Bonačić notably highlighted Šimenc's unique success as a dual international in two ball sports, even suggesting he was named the best defensive player at a handball World Championship. Numerous media outlets emphasized his unique status as a dual international in two team sports, a feat considered rare and almost unimaginable in modern sport, underscoring his significant cultural impact and recognition as a "legend" and "giant" of Croatian sport.

At the club level, Šimenc was a cornerstone of HAVK Mladost's golden era. He was instrumental in the team winning five national championships (Prvenstvo države) and four winter national championships (Zimsko državno prvenstvo). He also led them to four European Champions Cup titles in 1967, 1968, 1969, and 1971, solidifying Mladost's reputation as a dominant force in European water polo. His dedication to the club spanned two decades, from 1955 to 1975.

Beyond his playing days, Zlatko Šimenc transitioned seamlessly into coaching and academia. He coached Mladost, leading them to further success with a Cup Winners' Cup and a European Super Cup title in 1975. He also served as coach of the Yugoslav water polo national team from 1969 to 1971. Academically, he graduated from the Institute of Physical Education in Zagreb in 1966, later earning a master's degree and a PhD in kinesiology. He served as a respected professor at the University of Zagreb's Kinesiology Faculty from 1966 until his retirement, publishing approximately 60 scientific papers and books on handball and water polo. Professor Igor Jukić, a former student and later dean, described Šimenc as a "leading teaching authority," "excellent teacher," "top motivator," and a "giant of kinesiology".

Šimenc also held significant sports official roles, including at the Yugoslav Water Polo Federation (1980–82) and Croatian Water Polo Federation (1992–96), as a member of the Croatian Olympic Committee (1991–95), president of the Club of Olympians (1996–2000), and president of the Expert Commission of the Croatian Water Polo Federation (1992–1996). His immense contributions to Croatian sport were recognized with the "Franjo Bučar" annual award in 1998 and the prestigious "Franjo Bučar" lifetime achievement award in 2001.

Zlatko Šimenc will be remembered as a true sporting phenomenon, a brilliant academic, and a devoted family man whose influence resonated deeply within the sporting community and beyond. His sporting legacy continued through his children; his son, Dubravko Šimenc, also became an Olympic medalist in water polo, and his daughter Iva is a coach and former synchronized swimmer.