The Ramsar Convention (world's oldest environmental convention or treaty named after the town of Ramsar in Iran where it was launched in 1971) defines wetlands as:"Areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static, flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres."

The text of the Convention further elaborates that wetlands: "May incorporate riparian and coastal zones adjacent to the wetlands, and islands and bodies of marine water deeper than six metres at low tide lying within the wetlands".

In simple language, wetlands are areas where water meets the land. Examples of wetland habitats in Malaysia are mangrove forests, peat swamp forests, fresh water swamp forests, lakes, rivers, coral reef flats, rice fields, etc.