Ramsar sites are wetlands of international importance designated under the Ramsar Convention.
Ramsar sites are designated under the Convention on Wetlands of International Importance, agreed in Ramsar, Iran, in 1971.
They are designed to protect wetlands defined as "areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres".
They may also incorporate coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low tide lying within the wetland.
For more information on Ramsar sites in the UK, its Overseas Territories and Crown see here.