Raids took place in Hartlepool, Surrey, Oxfordshire and London on Tuesday.
The National Crime Agency (NCA) said the alleged ringleader of the network was among those detained.
Deputy director Andrea Wilson said people smuggling saw migrants "exploited for profit by criminals who have no regard for human life."
The penalties were "severe and life changing" and it was "simply not worth the risk", she said.
Investigators believe the alleged smugglers had contacts in France, Germany the Netherlands and Poland and used lorries and hired vans to move people to the UK from northern France. Some migrants are believed to have paid between £20,000 and £25,000 to try and reach the UK, the NCA said.
Financial investigators have identified bank accounts alleged to belong to the network, some showing hundreds of thousands of pounds in turnover.
The NCA said about £30,000 cash was recovered in the operation.
Branch commander Richard Harrison said the network "claimed to provide a top of the range service and charged accordingly".
"This activity represented a significant threat to both the safety of the migrants involved and the security of UK border controls," he said.