Migrants were pulled from the sea as they were rescued while trying to cross the Channel.
The PA news agency understands some people were in the water when help from the coastguard and lifeboats arrived on Wednesday.
All-weather lifeboats from Dover, Dungeness and Hastings were launched in response to the incident, the RNLI said.
In a statement, HM Coastguard said there were “a number of incidents” off the coast of Kent.
“HM Coastguard has been working with the French authorities co-ordinating the response to a number of incidents involving small boats off Kent today, January 31,” a spokesperson said.
“The French authorities and HM Coastguard sent resources in response.”
The number of arrivals on Wednesday will be confirmed when the Home Office publishes the latest figures on Thursday.
More than 1,000 migrants have arrived in the UK so far this year after crossing the Channel.
Home Office figures show more than 300 people made the journey at the weekend, with 112 recorded in two boats on Saturday and 276 on Sunday in five boats.
This takes the provisional total for 2024 to date to 1,057. No further crossings have been recorded since the weekend.
The highest number to cross in a single day so far this year was 358 in eight boats on January 17.
The latest arrivals follow a meeting between Home Secretary James Cleverly and his French counterpart, Gerald Darmanin, in Paris on Tuesday.
The pair reportedly agreed to wider and more regular use of drones in sky patrols to monitor migrants attempting to make the journey as part of existing agreements.
France has been tasked with stepping up efforts to prevent Channel crossings in recent years by deploying more police and drawing on extra equipment and facilities in the wake of deals with the UK worth £191.3 million between 2018 and 2022 and £480 million that Prime Minister Rishi Sunak promised to spend between 2023 and 2026.