When Do Basking Sharks Visit the UK? Season and Hotspots

The basking shark season month by month

The basking shark is the second-largest fish in the world, and in Britain and Ireland it is a summer visitor. A study of nearly 12,000 public sightings in UK waters from 1988 to 2008 found a strongly seasonal pattern, with sightings at their highest from June to August. The length of the season also varies from year to year, and was linked to a large-scale climate pattern over the North Atlantic.

Early starts do happen. In March 2022, a fisherman reported a gathering of at least 100 basking sharks southwest of Hook Head in County Wexford, Ireland, one of the largest groups ever recorded there.

Where to see basking sharks in the UK and Ireland

Sightings records show three main hotspots in UK waters.

Southwest England. Cornwall is the classic place to see basking sharks in England, particularly around the Land’s End peninsula and the Lizard, with sharks also seen off Devon and the Isles of Scilly. They often feed close to headlands and in sheltered bays.

Isle of Man. The waters off the island’s west and south coasts are one of the most reliable places in the Irish Sea. Local researchers have studied and tagged sharks there for many years.

Western Scotland. The Sea of the Hebrides, especially around the islands of Coll and Tiree, attracts large numbers of sharks each summer. In 2020 it was designated a Marine Protected Area, partly to protect them. Other wildlife of the region is covered in wildlife of Scotland.

Ireland. Basking sharks are regularly seen off the south and west coasts, from Waterford, West Cork and Kerry to Clare, the Aran Islands and Donegal. On calm days in late spring, dozens can sometimes be seen feeding close to shore along the Clare coast near Loop Head and Kilkee. More on Irish wildlife is in animals of Ireland.

Why basking sharks come in summer

Basking sharks follow their food. They feed on zooplankton, mainly small crustaceans called copepods, which multiply in coastal waters as the days lengthen and the sea warms in spring and summer. The sharks favor places where plankton is concentrated, such as headlands, islands, and fronts where tidal currents push different bodies of water together.

Surface sightings also depend on the weather. Sharks are easiest to spot on calm, sunny days, when their dorsal fin and tail tip break a flat sea and plankton swarms rise close to the surface. In rough weather they may still be there, but feeding deeper and out of sight. Other big summer visitors, such as the ocean sunfish, turn up in the same seas at the same time of year.

Courtship gatherings and breaching

Summer is not only about feeding. In the Hebrides, small groups of basking sharks have been seen swimming nose to tail in slow circles, behavior that researchers think is linked to courtship. Sharks there also breach, leaping clear of the water, which seems most common when many sharks are together.

Cameras towed behind sharks in the Sea of the Hebrides have recorded groups interacting below the surface. Even so, NatureScot notes that scientists still do not know whether basking sharks actually breed in Scottish waters. Very little is known about where they mate or give birth anywhere in the world.

Where do basking sharks go in winter?

Because basking sharks almost disappear from the surface in autumn, people once believed they spent the winter resting on the seabed after shedding their gill rakers. Tagging has shown this is wrong. A study of sharks tagged off Britain, published in 2003, found that they remain active all winter, moving into deeper water where they probably feed on plankton that has sunk to depths of hundreds of meters.

Later satellite tracking showed that the sharks follow different strategies. Researchers fitted 70 satellite tags to sharks off the west coast of Scotland and the Isle of Man between 2012 and 2015. In a study published in 2017, the sharks that were tracked long enough fell into three groups: some stayed in the waters of the UK, Ireland and the Faroe Islands, some went south to the Bay of Biscay, and others traveled even farther, to waters off Spain, Portugal and North Africa.

What tagging studies have revealed

Tracking has also shown that many sharks come back. Sharks tagged around Coll and Tiree returned to the same area in consecutive summers after spending the winter as far south as the Canary Islands. This loyalty to particular feeding grounds is one reason why protecting key areas works well for this species.

Some journeys are remarkable. A female tagged off the Isle of Man swam about 9,600 km (6,000 mi) across the Atlantic to Newfoundland in 82 days, diving to 1,264 m (4,147 ft) on the way. Such trips show that the sharks seen in British and Irish waters are part of a much wider ocean population. The IUCN lists the basking shark as Endangered worldwide, so these summer gatherings are important.

How to watch basking sharks responsibly

The best way to see basking sharks is from a headland on a calm summer day, or on a boat trip with an operator that follows a wildlife-watching code. Look for a tall, triangular dorsal fin with the tip of a tail fin a few meters behind it, moving slowly back and forth.

Basking sharks are protected by law throughout British and Irish waters, and they are easily disturbed. Boats should stay at least 100 m (330 ft) away, slow down, and never chase or cut across a shark’s path. The sharks are not dangerous, but they are huge and powerful, as explained in Are basking sharks dangerous? Sightings, ideally with photos, can be reported to the Shark Trust in Britain or the Irish Whale and Dolphin Group in Ireland.