The gruesome discovery of the bodies of the victims, aged 20 to 22, was made by a passer-by who then alerted community members, police said.
The suspects, aged 29 to 67, were arrested at Mbentse locality outside Mthatha on Wednesday, Eastern Cape police spokesperson Colonel Sibongile Soci said.
Soci said a 9mm pistol with 21 rounds believed to have been used during the attack, was confiscated.
They will appear in the Qumbu Magistrate’s Court on four counts of murder and the illegal possession of a firearm and ammunition.
Soci said the men were from Luxeni locality in Qumbu.
She said the motive for the killings was not yet known.
Acting Eastern Cape police commissioner Major General Andre Swart commended the police for what he described as a speedy arrest.