Alnmouth's coastline has multiple protected area designations. It lies at the southern end of the Northumberland Coast Area of Outstanding Natural Beauty and the (non-statutory) Northumberland Heritage Coast, both of which seek to protect its landscape in all aspects. The saltflats of the estuary and the south beach dune are a Site of Special Scientific Interest listed in 1988 as Alnmouth Saltmarsh and Dunes for its varied plant community. As part of the Environment Agency's Northumberland 4shores Project, in 2006, flood banks protecting of estuarine pasture were breached and shallow ponds created, to allow tidal action to recreate saltflats to provide habitats for wading birds, dissipate wave energy, and diminish the potential for flooding. The golf course area, north of the village, is registered as common land.
