The National Marine Park of Alonnisos Northern Sporades (Greek: Εθνικό Θαλάσσιο Πάρκο Αλοννήσου Βορείων Σποράδων, ΕΘΠΑΒΣ) was founded in Greece by Presidential Decree on May 16, 1992.

[1] Thomas Schultze-Westrum, a German zoologist and maker of animal documentaries, after a series of exploratory missions to the islands in 1976, noted the great ecological and biological value for the first time and proposed the creation of protected area.

Six years later, the local fishermen of Alonnisos Island accepted, after consultation, the prospect of establishing a park in the region and were committed to help with its protection.

In 1986 the Magnesia Prefecture issued the first order to protect the region, followed by the decisions of the Ministries of Environmental Affairs, Agriculture and Merchant Navy.

The newly formed Hellenic Society for the Study and Protection of the Monk seal (MOm), composed of young marine biologists, in 1990 set up a permanent team field in the area of the reserve and acquired the research vessel IFAW-ODYSSEAS to aid to the systematic monitoring of the population of the Mediterranean monk seal (Monachus monachus), which remained so until 2006.

Its main characteristics are the steep rocky slopes which run down to the sea and the caves, which are an important part of the habitat of the monk seal.

The geographic isolation of the area, its morphology, the limited degree of human interference and the excellent condition of the natural environment make the land and sea areas of the park an ideal habitat for many threatened species of plants and animals The islands are covered in Mediterranean coniferous forest and macchia vegetation such as the strawberry tree, phillyrea, the heather, rhamnus, the kermes oak, often in the form of treelike shrubs, and evergreen trees such as the maple, the wild olive, the Phoenician juniper and the rare tree Amelanchier chelmea.

Underwater sea-grass beds of Posidonia oceanica, which is particularly important for the development of other organisms and the retention and cycling of suspended particles and various substances in the marine environment, are widely spread and in good condition.