The number and classification of islands in Croatia varies over time and by different measurements, causing some domestic controversy when discrepancies are found.
The Croatian Bureau of Statistics uses data from the Geographical Department of the Faculty of Science of the University of Zagreb, which classifies a total of 1,185 islands, rocks and reefs: 48 inhabited islands, 670 uninhabited islands (Croatian: otoci), 389 rocks (hridi) and 78 reefs (grebeni).
The Hydrographic Institute of the Republic of Croatia classifies all landforms surrounded by water in the Adriatic Sea as islands (Croatian: otoci), islets (otočići) and rocks (hridi).
The categorization is determined according to their surface area.
Rocks are defined as islets smaller than 0.1 km², islets are between 0.1 and 1.0 km² and islands proper are bigger than 1.0 km².