With the mission to "provide leadership and encourage partnerships in caring for the environment by inspiring, informing and enabling nations and people to improve their quality of life without compromising that of future generations", UNEP has been creating a basis for comprehensive consideration and co-ordinated action within the UN on the problems of the human environment.

UNEP makes a particular effort to nurture partnerships with other UN bodies, as well as to enhance the participation of the private sector, the scientific community, NGOs, youth, women, and sports organizations in the achievement of sustainable development. Today, the challenge before UNEP is to further catalyze, promote and implement an agenda for sustainable development - an environmental agenda that is integrated strategically with the goals of economic development and social well-being. UNEP has several water-related programmes.

The UNEP Regional Seas Programme was initiated in 1974 as a global programme to be implemented through regional components. At present, it includes 13 regions involving more than 140 coastal states and territories. It is an action-oriented programme and focuses not only on the mitigation or elimination of the consequences but also on the causes of environmental degradation. Each regional action plan is formulated according to the needs and priorities of the region as perceived by the governments concerned.

UNEP is also responsible for the Secretariat set up to implement the 1985 Global Programme of Action (GPA) for the Protection of the Marine Environment from Land-based Activities. The GPA is aimed at preventing the degradation of the marine environment from land-based activities by identifying marine pollution problems, by establishing priorities, and by setting management objectives for priority problems.

The UNEP Freshwater Programmes comprise structured programmes of environmental inventory, analysis, diagnosis and action planning. Such programmes have been or are presently being developed and implemented for a number of large river and lake basins in Africa, Asia and South America. Within the UN system, UNEP is the lead agency for the water resources component of the UN Special Initiative for Africa (UNSIA). In this capacity, UNEP is chairing the UN Working Group mandated by the Secretary-General to address the critical water problems in Africa.

UNEP is, furthermore, one of the implementing agencies for the Global Environment Facility, GEF. The UNEP portfolio of GEF funded activities in international waters include global assessments, transboundary diagnostic analyses (TDAs) of shared water bodies, support to the implementation of strategic action programmes for marine and freshwater areas, and support to integrated management of shared freshwater bodies.