Nearly 400 people in 26 boats made their way across the Channel to reach the UK in one day.
Many of the small vessels were intercepted by Border Force before reaching Kent on Tuesday.
Dozens of people were seen arriving in Dover harbour wrapped in blankets and wearing lifejackets.
They included children, including one in a pink jacket who was too young to walk.
Many had to queue before they were allowed to disembark from Border Force boats because of the volume of arrivals.
Border Force had at least five boats in operation: cutters Seeker and Searcher and patrol boats Hunter, Speedwell and Eagle.
A police boat was also operating in the Channel along with a coastguard helicopter and the RNLI.
The agencies were kept busy along miles of coastline across East Sussex and Kent for several hours.
In France, authorities prevented 10 crossings yesterday involving more than 90 people in addition to detections on the beach and inland.
French law enforcement also destroyed a number of boats to prevent further crossings.
It brings the number who have made it to the UK in September to at least 1,880, according to PA news agency.
This is roughly the same number believed to have crossed in the whole of 2019.
The Home Office is now working on "new tactics" to try and tackle the situation.
'France is a safe country and asylum seekers already in France should claim asylum there...'
Clandestine Channel threat commander Dan O’Mahoney said: "Yesterday I met with the French Ambassador to the UK where I reiterated the urgency to tackle the issue.
"We discussed how best the UK and France can use new tactics and operational activity to stop the boats leaving French shores in the first place.
"Yesterday French law enforcement conducted nine operations across the Calais region, destroyed a number of boats so individuals could not attempt to cross, and prevented at least 98 migrants from crossing to the UK - but we acknowledge there is more to be done.
"France is a safe country and asylum seekers already in France should claim asylum there."
A Home Office spokesman added: "We continue to return those who do not have a legitimate asylum claim despite barriers to removals under the Dublin Regulations and legal challenges.
"Our efforts to facilitate entirely legitimate and legal returns are often frustrated by last minute challenges submitted hours before a scheduled flight.
"These claims are very often entirely without merit, but must be given proper consideration, leading to removal being rescheduled.
"This can effectively result in the timing out of a return due to stringent Dublin Regulations."