Four migrants died overnight and a fifth was found dead on Sunday after trying to reach Britain from northern France despite freezing temperatures, the French maritime authority said.
The group was attempting to reach a vessel off Wimereux when their small boat got into difficulty around 2am (01:00 GMT), the maritime prefecture told AFP.
"We have four dead migrants and one migrant in a critical condition at the hospital in Boulogne-sur-mer," said one official.
A fifth migrant was found dead late Sunday morning, the maritime prefecture said.
A tugboat patrolling the coast went to the rescue and found the bodies, the first reported migrant deaths on the Channel in 2024.
The region around Calais, the jumping-off point for the shortest crossing to England, has long been a magnet for migrants.
More than two decades after the closure of a Red Cross centre in Sangatte, hundreds of people still live in tents and makeshift shelters near Calais and Dunkirk, hoping for a chance to make the crossing hidden in a truck or aboard a small boat.
The boats are a political priority for the British government and a bone of contention with France, as tens of thousands of people a year have been making the dangerous crossing.
According to the British government nearly 30,000 migrants crossed the Channel from mainland Europe to Britain in small boats in 2023, an annual drop of more than a third.
In November 2021, at least 27 people drowned when their dinghy capsized.
(FRANCE 24 with AFP)
