Eleven migrants were intercepted by Border Force as they crossed the Channel in a small boat.
A dinghy was seen travelling towards the UK coast at about 09:00 BST.
The group, who said they were from Iran and Niger, were transported to Dover and passed to immigration officers for interview, the Home Office said.
A further 24 migrants were rescued by the French coastguard and taken to Calais after their dinghy got into difficulty about 4km north of Dunkirk.
More than 950 people, including at least 80 children, have crossed the Channel in small boats this year.
Prime Minister Boris Johnson said his message to migrants crossing the Channel is “we will send you back.”
He added: “If you come illegally you’re an illegal migrant and I’m afraid the law will treat you as such.”
About 65 people who arrived in the UK illegally by small boat have been returned to European countries, the Home Office said.
It said it was monitoring the “ongoing situation” and “working closely at all levels with French authorities.”
Home Secretary Priti Patel is due to “raise this issue with her French counterpart in the coming days”.