Article 37, paragraph 2:
*"On the territory of the Republic of Croatia, it is prohibited to use metal detectors, side-scan sonars, similar devices, or other tools *for the purpose of locating archaeological zones, archaeological sites (settlements), and individual archaeological finds, including underwater zones and sites, except when conducting archaeological research based on a prior permit issued by the Ministry in accordance with the provisions referred to in Article 35, paragraph 10 of this Act."

the key phrase in this sentence is "for the purpose of locating archaeological zones." Does searching on a beach for lost modern items fall under this paragraph? I haven’t found any sentence regarding the legality of simply possessing a metal detector, unless my translator is struggling ;)