Henry of Coquet lived as a hermit on the island until his death in 1127. The Benedictines of Tynemouth Priory later founded a small monastery on the southwestern shore, and the surviving stonework of that medieval foundation was eventually absorbed into the buildings of the nineteenth-century lighthouse. Whether Henry preferred the solitude for spiritual reasons or simply for the silence of the sea is not recorded, but Coquet Island offered both. It is a low, grassy mass owned today by the Duke of Northumberland, surrounded by clear water and currents that have wrecked many a ship between here and the mainland.

Trinity House built Coquet Lighthouse in 1841 at a cost of £3,268. James Walker designed it - a white square sandstone tower with walls more than a metre thick, ringed by a turreted parapet. The first keeper was William Darling, elder brother of the famous Grace Darling. A first-order fixed dioptric lens, made by Isaac Cookson of Newcastle, sat in the lantern room with mirrors that were replaced by refracting prisms ten years later. Red sectors warned ships of Hauxley Point to the south and Boulmer Rocks to the north from 1854. An eight-wick mineral-oil burner replaced the original lamp in 1891. The light has been solar-powered since 2008, and in 2025 Trinity House announced that the original 1841 optic, exhibited for years at museums in Penzance and at Souter Lighthouse, would return to Coquet to work again alongside a modern LED.

The Royal Society for the Protection of Birds manages Coquet Island as a seabird reserve, and it carries an importance out of all proportion to its size. The largest colony of the endangered roseate tern in Britain nests here, and conservation work - including nest boxes that shelter the eggs from gulls and bad weather - has lifted the population to 118 pairs in 2018, climbing from very low numbers. Around 18,000 pairs of puffins nested here in 2002, the most numerous species on the island. Sandwich terns, common terns, Arctic terns, black-legged kittiwakes, fulmars, three other gull species and eider duck all breed on the island. The combination of a small protected area and intensive management has made Coquet one of the most important seabird sites on the east coast of Britain.

Public landing on Coquet Island is prohibited; the birds are too vulnerable to disturbance. Seasonal wardens live on the island throughout the summer to protect the nesting colonies. What visitors get instead is a boat trip from Amble, with operators running close to the shore in good weather so that the puffins, the terns, and the kittiwakes can be seen well. The lighthouse stands above it all, its white walls still doing the job they were built for in 1841, and Henry of Coquet's old monastery is buried in the masonry below. It is a place that has worked hard for its inhabitants for nine centuries - first a hermit, then keepers, now seabirds - and still asks visitors to keep their distance and let it work.