The purpose of this research is to check and identify international legal issues caused by climate change and sea level rise, such as its impact on the small island states and maritime delimitation, and is to suggest legal and policy solutions to resolve this matters. This study is presented with some analyses on the issues and the problems related with small island states and maritime delimitation. Various policy options to solve this problem are provided. The first issue to discuss is about the feasibility of adoption of "Equity" to offer preferential treatment to small island states and its specific condition for actualization, if possible, are reviewed afterwards, since the small island states are the most vulnerable group confronted by the rising sea level. Assuming some or all of the small island states’ territory is submerged, this study examines a problem whether if the state itself should be naturally become extinct and a method how to protect its people. Also, this research checks if the maritime jurisdiction could be maintained despite the disappearance or changes of the baseline. Also, this study deals with the effect of sea level rise on the maritime demarcation and the related issues. Especially it considers a problem whether or not the effect of maritime delimitation agreement between the states remains intact despite the changes in the baseline due to the sea level rise. It also deals with the balance of interests between the contracting parties and the non-contracting party. The maritime delimitation between the contracting parties, inevitably, has an international dimension and thus has an impact on the other states. It concludes that if the contracting parties take measures to stick to the established boundaries even though a new maritime demarcation is needed to reflect the changes of baseline stemming from the sea level rise, those measures could constitute an impingement on the rights of the third party. The study further examines the proper way of distribution of right between the coastal and non-coastal states, and reviews the role of the Third-party Dispute Settlement Body. Finally, it provides with various legal and institutional methods to resolve the problems related with the effect of sea level rise on the maritime delimitation and the related issues. As a suggestion, it suggests the appropriate measures to protect inhabitant of small island states. It also proposes the introduction of “Special Waters” including the concept of ‘waters established by Convention’ through the reinterpretation of “historical waters” and ‘buffer zone’ as a method of spatial solution, the conclusion of ‘Agreement for Implementation of UNCLOS for Sea Level Rise and Maritime Delimitation, and the generation of the international consensus through the process of the revision of the UNCLOS, and the formation of new customary international law with local customary law in the lead.