Some 872 migrants aboard 15 different vessels made the perilous journey across one of the world's busiest shipping lanes on Saturday, beating this year's previous 24-hour high of 756 on August 10.
It brings the total number to have arrived on the shores of southeast England so far in 2023 to more than 21,000.
That is less than the levels seen at this point last year, but still presents a major political and practical headache for the UK government.
London promised tighter border controls after the country left the European Union, and Prime Minister Rishi Sunak has made "stopping the boats" a key priority.
His Conservative government has branded the cross-Channel route "illegal" and passed legislation blocking asylum applications from anyone arriving without prior authorisation.
It also wants to send migrants to Rwanda for processing and resettlement there, but both policies are on hold amid a legal challenge to the African relocation plans.
More than 100,000 migrants have crossed the Channel on small boats from France to southeast England since Britain began publicly recording the arrivals in 2018.
They have strained Britain's asylum system, with a growing backlog of more than 175,000 people, including children, waiting for an initial decision by the end of June.
The route has also repeatedly proved perilous, with numerous capsizes and scores of migrants drowning in the Channel's waters over the last decade.
