Mayo has the longest coastline of any county in Ireland.

It has 802 km of soft coastline with habitats such as sand dunes, machair and sandy beaches. Hard coastline is 366 km long (rocky shore and sea cliffs) while offshore islands have 302 km in coastline.

Sand dunes may have different shapes and forms with a range of habitats. Prime examples of sand dune systems in Mayo can be found in the Mullet peninsula and at Kilcummin Head.

The Portland Moth is a rare species that lives in Mayo's sand dunes.

Machair is a unique type of sand dune habitat found only in the west coast of Ireland.

Machair refers to grassy plains formed on wind-blown calcareous sands. It is flat and close to water and is usually grazed and heavily producing a short turf grassland very rich.

Mayo has the longest coastline of any county in Ireland. Machair is a unique type of sand dune habitat found only in the west coast of Ireland.

Some of the most important machair examples in Mayo are on the Mullet peninsula and Achill Island.

A variety of birds including dunlin, redshank and snipe can be found in machair habitats such as some invertebrate (Irish click beetle)