The Home Office reported that more than 600 migrants crossed the English Channel on Sunday, making it the most people to do so in a single day so far this year.
Twelve small boats carrying 616 people were seen leaving France for the area.
On April 22, 497 people reached this year's previous daily high.
More than 8,000 migrants have started their journey so far this year, which is about 2,000 fewer than at this time last year.
Speaking last week in Dover, Prime Minister Rishi Sunak claimed that his strategy for reducing the number of migrants using boats to cross the English Channel was bearing fruit and that for the first time, numbers were down.
Crossings to the UK were down by a fifth, and figures for Albanians traveling to Britain were down by 90%, according to Mr. Sunak, who spoke with BBC political editor Chris Mason.
The total had just surpassed 10,000 at this point last year. Last year, there were 45,755 crossings in total.
