The National Crime Agency (NCA) said those arrested include doctors, teachers, scout leaders, care workers and former police officers.
More than 400 children have been protected as a result, the agency said.
Arrests were made across the UK and the majority of those held had no previous contact with police.
The NCA said 39 of those arrested are registered sex offenders.
Charges already brought range from possessing indecent images of children to serious sexual assault.
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NCA deputy director general Phil Gormley said sex offenders should understand they cannot avoid detection while using the internet, even on the so-called "dark net".
"Some of the people who start by accessing indecent images online go on to abuse children directly. So the operation is not only about catching people who have already offended - it is about influencing potential offenders before they cross that line," Gormley said.
"We want those offenders to know that the internet is not a safe anonymous space for accessing indecent images, that they leave a digital footprint, and that law enforcement will find it," he added.
Officers have searched 833 properties and examined 9,172 computers, phones and hard drives.
The national policing lead for child protection and abuse, Chief Constable Simon Bailey, said, "During this operation, we've targeted offenders accessing child abuse images.
"Police must continue to use a range of investigative techniques targeting all forms of abuse if we going to protect children and bring offenders to justice.
"Chief officers are committed using all the tools available to them because nothing is more important in policing than protecting vulnerable people."