More than 270 people crossed the English Channel in 10 small boats on Thursday, the Home Office confirmed.
Several young children were among the 271 migrants who were brought ashore in Dover by UK Border Force officers.
French authorities also intercepted 75 people in three small boats, despite near-freezing temperatures on the Channel on Thursday.
More than 28,000 migrants made the journey throughout 2021, compared to 8,400 in 2020.
Thursday's figure is more than the entire total for January last year. More than 450 people have made the trip across the Channel in January so far.
Minister for Justice and Tackling Illegal Migration, Tom Pursglove, said: "The government is reforming our approach to illegal entry to the UK and asylum by making the tough decisions to end the overt exploitation of our laws and its impact on UK taxpayers."
The English Channel is one of the most dangerous and busiest shipping lanes in the world.
Many migrants come from some of the poorest and most chaotic parts of the world, and many ask to claim asylum once they are picked up by the UK authorities.