As many as 963 herbarium sheets featuring 76 aquatic plant taxa from the ZA collection were digitised and published online through the Virtual Herbarium. Aquatic plants have been collected over a period of 176 years, with three peaks (second decade of the 20th century, in the 1940s and 1950s, and in the current decade). Most of the specimens were collected in Croatia and a smaller number in neighbouring and geographically close countries. The importance of the collection is expressed through the specimens of many rare and threatened species, because it represents the only evidence of their presence in Croatia (the regionally extinct Caldessia parnassifolia, as well as Luronium natans, Callitriche platycarpa, C. truncata, C. hermaphroditica, Potamogeton alpinus, P. compressus, P. polygonifolius, Nuphar × spenneriana and Sparganium minimum). The collection in ZA is a valuable source of data about the historical and recent distribution of aquatic plants that constitute a foundation for the estimation of distribution changes, threat assessment and conservation policies.