The criminal protection of the environment is becoming an increasingly pivotal concern in contemporary legislation, particularly within the European Union, which is continuously striving to enhance the legal framework for environmental and biodiversity protection. This thesis analyses the legal regulation of the environment in the Republic of Croatia, with a particular emphasis on criminal protection in accordance with Directive (EU) 2024/1203 of the European Parliament and of the Council on the protection of the environment through criminal law. This introduces more stringent measures and sanctions for criminal offences against the environment, replacing the previous Directives 2008/99/EC and 2009/123/EC. This section of the thesis addresses the specific criminal acts against the environment in the Republic of Croatia. The types of criminal acts are discussed, along with the specific institutions that are involved, including the issue of effective remorse and the responsibility of legal persons. The final section of the paper addresses the legal status of Marjan Forest Park, with particular attention to matters of ownership, illegal construction, and the enforcement of protection measures within this protected area. By analysing this specific case, the paper identifies the challenges and opportunities for improving the legal protection of the environment at the local level. Through a comprehensive analysis of existing legislation and practice, the paper aims to provide insight into current challenges and potential guidelines for the further development of criminal environmental protection.