Prološko blato is a large swamp region of the Imotsko polje (Imotski field) and has been protected since 1971.
Blato is a typical example of flooded karstic fields in Dalmatia which nowadays have mostly been destroyed by drainage. A small part is covered in water for the entire year (Prološko jezero- Prološko lake) and the whole field is covered in water for part of the year. In the period when the entire Blato (swamp) is flooded, only the islet of Manastir remains dry. Prološko Blato has great aesthetic and ecological values thanks to the numerous swamp birds which come here during migration.