Around 40 people have been arrested in a series of coordinated raids involving law enforcement officials from the UK, Belgium, Germany, France and the Netherlands.
The operation has been led by the National Crime Agency in the UK and Europol and Eurojust across mainland Europe.
NCA officers arrested six people in London, two on suspicion of conspiring to facilitate illegal immigration.
Two other men were arrested immigration offences, while a man and a women were detained on suspicion of possessing class-A drugs with intent to supply.
The operation has been led by the National Crime Agency in the UK
NCA
The NCA also deployed officers to Germany
NCA
Arrests were also made in Germany, the Netherlands and France.
The National Crime Agency said many of those arrested across Europe had been “targeted as a result of evidence being supplied by the NCA to international partners".
The NCA also deployed officers to Germany where more than 60 small boats and 900 life jackets were recovered from a farm near Osnabruck.
More boats, outboard motors, lifejackets and pumps used to inflate the small boats, were found in the Netherlands.
In total, the operation seized 135 boats, 45 outboard motors and more than 1,200 life jackets.
The operation follows the arrest in May of a man living in London, who is suspected of being a leading figure in the network.
Hewa Rahimpur, 29, and originally from Iran, is wanted by authorities in Belgium and now faces extradition from the UK.
NCA Deputy Director of Investigations Jacque Beer said: “This international investigation is targeting one of the most significant and most prolific crime groups involved in supplying small boats and moving migrants across the Channel.
“The NCA has played a key role, which has been months in the planning.
"We worked closely with partners in France, Belgium, Germany and the Netherlands to identify suspected members of this network.
“Criminal gangs involved in small boat crossings should know that we are committed to throwing the full weight of European law enforcement at curtailing your activities.”
Reacting to the operation to dismantle a suspected people smuggling gang, Home Secretary Priti Patel said: "This hugely significant operation involving 40 arrests sends a clear message to the criminal people-smuggling gangs across Europe & beyond: 'We’ll stop at nothing to end your trade, bring you to justice & save lives.'"