The three Malaysians, two Indonesian nationals and a Filipino national emerged from the Kamunting Detention Centre here at 8.30am.
"You have nothing to worry about, all of you are now free," the director of the centre, prisons assistant commissioner Mohd Roslen Ramli, told them upon their release.
The ISA was revoked and substituted with the Security Offences (Special Measures) Act 2012 on July 31 last year.
Home Minister Datuk Seri Dr Ahmad Zahid Hamidi announced on Saturday that the six remaining ISA detainees would be freed on Sunday.
The six people, in normal attire and carrying a bag and a box containing personal items, seemed cheerful and expressed gratitude over their release.
Just as they stepped out of the main door of the centre, they chatted with several of the officers and staff and posed for photographs with them.
They thanked the officers and staff for having taken care of them during their detention over the past two years.
The six were detained on Nov 14, 2011, for being members of the Sabah Darul Islamiah (DI), an alleged terrorist group. - Bernama