Though the United Nations will face numerous challenges on the world"s oceans in the next decades, it has not yet developed the capability to operate effectively in the areas of maritime peacekeeping or enforcement. This study examines the various regional maritime challenges confronting the United Nations and describes several organisational and experiential models - ranging from Claiborne Pell"s early suggestions for an International Sea Patrol, through various NATO standing forces and US Coast Guard models, to recent experience gained through multinational maritime co-operation in the Gulf - from which planners might extract important lessons. The author concludes with specific recommendations for the establishment of a UN Maritime Agency, seeing that step as crucial in the effort to ensure peace and prosperity on the world"s oceans.