The objective of this paper is to review and analyze a set of international treaties that focus on environmental protection and sustainable development through cooperation at both international and regional levels. It examined different environmental agreements made during different periods on matters such as transboundary fish stocks, transboundary waters protection, anti-desertification law, and other relevant issues. This study reviewed the United Nations Agreement on Straddling Fish Stocks of the year 1995, which aims at the long-term conservation and sustainable utilization of fish stocks. It also highlighted the critical importance of the Helsinki Convention (1992) on the Protection and Use of Transboundary Watercourses for long vital improvements in water quality and public health protection into the regional and international cooperation through participatory approaches. The study considered the United Nations Convention to Combat Desertification (1994) in its fight against desertification and the alleviation of drought impacts in drought-stricken regions, particularly Africa. It also addressed the United Nations Convention on the Law of Non-Navigational Uses of International Watercourses (1997) for the sustainable management and protection of transboundary waters and jointly the Espoo Convention (1991) which made environmental impact assessments a requirement in a transboundary context. From these treaties, the study brought out the imperative of strengthening international and regional co-operation to support the application of sustainable development principles and protect natural resources. It underscored that countries need to be capacitated to cope with climate change and policy and mechanism should be put in place that would ensure harmonious integration of economic growth with environmental protection. The findings indicated that these agreements are essential for realizing global environmental goals and play a significant role in fostering a more sustainable environment. To sum up, a series of recommendations were put forth aimed at improving the effective execution of these agreements by promoting greater international cooperation, elevating environmental awareness, and increasing investments in environmental research and development.