Issues relating to the protection of the marine environtment are of concern, including by international law. This research discusses the prtection and preservation of the marine environment according to international law. This research is a normative legal research. The approach used is the statutory approach. The research results show that the protection and preservation of the marine environment receives serious attention by international law, especially through regulation through the 1982 Nations Convention on the Law of the Sea (UNCLOS) which fully regulates the protection and preservation of the marine environment in a Chapter, namely Chapter XII which consists of 45 articles (192-237). In this Chapter there are several important aspects relating to the protection and preservation of the marine environment, namely the existence of general obligations of countries in terms of protecting the marine environment (Articles 192-160), obligations of the state in terms of pollution (Articles 194-196), global cooperation and in the framework of protecting the marine environment (Articles 197-201), technical assistance (Articles 202-203), environmental monitoring and analysis (Articles 204-206), making laws and regulations and accompanying law enforcement (Articles 207-234), responsibilities and compensation obligations (Article 235), immunity rights (Article 236), obligations under other conventions concerning the protection of the marine environment (Article 237). Persoalan berkaitan perlindungan lingkungan laut menjadi perhatian, termasuk oleh hukum internasional. Penelitian ini membahas perlindungan dan pelestarian lingkungan laut menurut hukum internasional. Penelitian ini adalah penelitian hukum normatif. Pendekatan yang digunakan adalah pendekatan perundangan-undangan. Dari hasil penelitian didapatkan hasil bahwa perlindungan dan pelestarian lingkungan laut mendapatkan perhatian serius oleh hukum internasional, terutama melalui pengaturan melalui Nations Convention on The Law of the Sea (UNCLOS) 1982 yang secara lengkap mengatur mengenai perlindungan dan pelestarian lingkungan laut dalam suatu Bab, yaitu Bab XII yang terdiri atas 45 pasal (192- 237). Dalam Bab tersebut terdapat beberapa aspek penting yang berkaitan dengan perlindungan dan pelestarian lingkungan laut, yaitu adanya kewajiban umum negara-negara dalam hal perlindungan lingkungan laut (Pasal 192- 193), kewajiban negara dalam hal pencemaran (Pasal 194-196), kerjasama global dan regional dalam rangka perlindungan lingkungan laut (Pasal 197- 201), bantuan teknik (Pasal 202-203), monitoring dan analisa lingkungan (Pasal 204-206), pembuatan peraturan perundang-undang disertai penegakan hukumnya (Pasal 207-234), tanggung jawab dan kewajiban ganti rugi (Pasal 235), hak kekebalan (Pasal 236), kewajiban-kewajiban berdasarkan konvensi lain mengenai perlindungan lingkungan laut (Pasal 237).