Samata Ullah, 33, from Cardiff, allegedly provided training in encryption programs for ISIS members.
Ullah was arrested in a Cardiff street on September 22 following an investigation by the Metropolitan Police counter terrorism command and the Welsh extremism and counterterrorism unit.
The 33-year-old allegedly supported ISIS using expertise he learned while working as a computer technician. He has been charged with possessing a USB stick "that had an operating system loaded on to it for a purpose connected with the commission, preparation, or instigation of terrorism." He allegedly disguised the USB stick as a cufflink.
RT reports that police and crime commissioner for South Wales Alun Michael said "Whilst early in the investigation we are not linking this to any other previous operation in Cardiff and there is no heightened risk in the Cardiff area. Whether in the street, workplace or online, those who seek to promote hatred and violence, whether based on race, religion, political affiliation, gender or sexuality, have no place in Wales or in Britain."
Ullah was reportedly due to appear at Westminster Magistrates' Court on Wednesday morning.