Ophioglossum azoricum is native to islands in the northern Atlantic Ocean and adjacent westernmost Europe from the Azores north to western France, the British Isles, Iceland and Greenland. It also occurs in the Toscana region of Italy.
This species mostly occurs on bare or shortly vegetated ground on exposed coastal clifftops. An exception to this habitat preference is populations in the New Forest, Hampshire where plants occur in tightly grazed damp grassland in a non-maritime setting.
The frond of Ophioglossum azoricum consists of a single, pointed leaf blade and a narrow pointed spore-bearing spike on a stalk. The spike has about 4-18 segments on each side, each of which opens up when ripe to release spores. The sterile blades are broadest near the middle and taper towards both ends.
This taxon is sometimes treated as a subspecies of Ophioglossum vulgatum, as Ophioglossum vulgatum ssp. ambiguum (Coss. & Germ.) E.F. Warburg.
This species has a chromosome number of 2n=c.480.