More than 470 people crossed the Channel from France on Monday, taking the provisional total for 2023 to 25,330.
On Saturday 537 people made the journey, with a further 28 on Sunday.
Experts said the UK government data shows human traffickers have taken advantage of the benign weather.
The French tug boat Abeille Normandie shadowed one inflatable dinghy carrying as many as 50 people, none wearing life jackets, as it motored towards British waters earlier this week.
The role of the tug, chartered by the French coastguard, was to ascertain “the state it's in, the number of souls on board and whether they are wearing life jackets or not,” said the vessel's skipper, who identified himself as Captain Mickael, in accordance with protocols.
“Then we'll follow it in order to be ready to intervene if a problem arises,” he added.
After entering British waters, the dinghy, sitting low in the water, was met by a British search-and-rescue vessel, which the migrants boarded, an agency photographer said.
In March the UK agreed to pay France around £480 million ($579 million) over three years to try to stop migrants making the illegal crossings after total arrivals reached more than 45,000 in 2022.
But the traffickers are constantly changing strategy, said Veronique Magnin, spokeswoman for the French coastguard in the Channel and North Sea. “They are very well organised,” she said.
UK government figures show the number of migrants detected crossing to Britain from France by sea so far this year stands at a provisional 25,330 – around 23 per cent below this point last year.
More than 33,000 people had made the crossing by October 2, 2022, with 45,774 arrivals in total last year.
Nine boats were detected on Monday, which suggests an average of about 52 people crossed the Channel per boat.
On September, 2, almost 900 migrants crossed the English Channel in small boats, the highest number on a single day so far this year.
The Home Office reiterated that the “unacceptable” number of people making the crossing is “placing an unprecedented strain on our asylum system”.
It added that its priority remained to “stop the boats”, with the Small Boats Operational Command working alongside French authorities and other agencies to disrupt people smugglers.
A spokesperson added: “The government is going even further through our Illegal Migration Act, which will mean that people arriving in the UK illegally are detained and promptly removed to their country of origin or a safe third country.”
Prime Minister Rishi Sunak has made stopping the crossings one of key pledges for this year.