The trio are Adel Kamel Haji, Abdullah Majed al-Nuaimi and Salman Ibrahim al-Khalifa, Information Minister and State Minister for Foreign Affairs Mohammad Abdul Ghaffar said in remarks carried by the state BNA news agency.
Salman Ibrahim al-Khalifa is a member of Bahrain's ruling family.
Abdul Ghaffar said the imminent release of the three was the fruit of efforts by Bahraini leaders, who had repeatedly raised the issue with US authorities.
The three "would be referred to the public prosecution ... within the framework of the laws in force in Bahrain. The government has prepared a programme to rehabilitate them and reintegrate them in society," the minister said.
Manama would continue its efforts to obtain the release of the other three citizens remaining in Guantanamo, Abdul Ghaffar added.
The three to be freed Saturday do not include a Bahraini detainee who was reported to have attempted suicide during his lawyer's visit in a sign of growing desperation among the camp's inmates.
The Washington Post reported on Tuesday that Jumah al-Dossari, who has been held since late 2001 after being seized in Pakistan, slashed his arm and hanged himself from the ceiling during a bathroom break from talks with his US lawyer on 15 October.
The treatment of prisoners at the
US naval base raised controversy
While suicide attempts have been reported before in the Guantanamo prison, it was the first to be witnessed by an outsider.
According to Amnesty International, al-Dossari has undergone frequent beatings, torture and long stretches of solitary confinement.
As many as 200 inmates are reported to have taken part in a rolling hunger strike since August to protest conditions at the prison. According to the Post, two dozen are being force-fed by prison staff.
About 500 people are being held at the Guantanamo detention centre without charges, most of them captured in 2001 in Afghanistan.
The camp has been the focus of worldwide controversy after allegations that US forces have abused detainees.
Five Kuwaiti nationals released from Guantanamo returned home on Friday.