More than 3,100 people have made the journey to the UK compared with around 1,600 at the same time last year, according to recent analysis.
Crossings have spiked since March last year because of Covid-19 travel restrictions and increased border security, according to the National Crime Agency (NCA).
Criminal gangs have also started using bigger boats to try to transport migrants into the UK, targeting small ports away from the busy Dover Strait.
Numbers of people trying to enter the UK hidden in vehicles on ferries or aboard flights fell during 2020, but returned to pre-lockdown levels in the final weeks of the year, the agency said in its annual National Strategic Assessment.
Overall the agency saw a decrease in overall organised immigration crime, despite the spike in small boat crossings.
The report, published on Tuesday, comes after Priti Patel pledged wholesale reform of the UK’s “broken” immigration system and unveiled plans for a “fully digital border” on Monday.
The data shows more than 3,100 people have succeeded in crossing the English Channel aboard small boats so far this year, continuing a sharp rise seen since April 2020.
More than 8,400 people crossed to the UK aboard small boats in 2020 in a record year.
The Home Secretary has repeatedly vowed to make the dangerous route “unviable” but crossings have surged.
As well as using dinghies and inflatable boats – many of them unseaworthy and in disrepair – organised crime groups (OCGs) have been observed using bigger boats, according to the NCA.
The NCA assessment said: “OCGs have attempted to transport migrants into the UK using larger vessels landing at small ports away from the Dover Strait.
“Migrants transported via this method have a higher chance of being exploited by UK-based criminals than those detected by law enforcement arriving by small boat.”
In November, 72 people were found crammed onto a 30-metre fishing boat off the coast of East Anglia.
The boat had sailed from the Ostend area of Belgium, the NCA said.
Tim Naor Hilton, chief executive of Refugee Action, said: “People smugglers will be over the moon at the Home Secretary’s drive to harden borders, which give desperate refugees little other choice than to pin their hopes on these criminals.
“This Government must create more routes to protection for people fleeing war and persecution, including introducing humanitarian visas and building an ambitious resettlement scheme that welcomes at least 5,000 refugees a year.”
A Home Office spokesperson said: “Our new plan for immigration will overhaul our asylum system and speed up the removal of failed asylum seekers.”