Two of the soldiers also are accused of assault and another is charged with seeking to destroy evidence.
In all, five soldiers have been charged with premeditated murder in the killings. All are assigned to B Company, 2nd Battalion, 1st Infantry Regiment, 5th Stryker Brigade Combat Team, 2nd Infantry Division.
The Army did not say what motives might have been involved.
The brigade, which made its first deployment to Afghanistan in July, has seen heavy fighting against Taliban insurgents and suffered 33 combat deaths. Two other soldiers have died of illness and another in a vehicular accident.
The three civilians killed near the Army's Forward Operating Base Ramrod in southern Afghanistan are identified as Gul Mudin, who died sometime in January; Marach Agha, killed on or about Feb. 22; and Mullah Adahdad, killed on or around May 2.
Officials at Lewis-McChord said Pvt. 1st Class Andrew Holmes, 19, of Boise, Idaho, Spc. Michael Wagnon II, 29, of Las Vegas, Nev., and Spc. Adam Winfield, 21, of Cape Coral, Fla., were charged Tuesday with one count each of premeditated murder.
Staff Sgt. Calvin Gibbs, 25, of Billings, Mont., and Spc. Jeremy Morlock, 22, of Wasilla, Alaska, each were charged earlier this month with three counts of premeditated murder and one count of assault.
The charging sheets, with the names of the accusers and officers involved blanked out, say Morlock and Gibbs shot Agha and used fragmentary grenades and their rifles to kill Mudin and Adahdad.
Holmes is accused of throwing a grenade at and shooting Mudin, Winfield of doing the same to Adahdad, and Wagnon of shooting Agha.
The documents also allege Morlock hit and kicked a person on May 5 and spat in a victim's face. Gibbs also is accused of hitting and kicking a person on that date. All identifying information is redacted, including names, gender, whether one or more victims were involved and whether they are civilians.
Wagnon is further accused of impeding a criminal investigation by asking another soldier to erase a computer hard drive that contained evidence of the killings.
Spokeswoman Lt. Col. Tamara Parker said Gibbs was charged June 8 in Kuwait and is in transit to Lewis-McChord, a joint Army-Air Force base south of Tacoma. Morlock was charged June 4. He and the other three soldiers are being confined at the base, as Gibbs will be when he arrives.
The next step for the soldiers will be Article 32 hearings, similar to a grand jury. Officers to lead those proceedings have not yet been appointed and no dates for the hearings have been set, Parker said.
It could not be immediately determined whether defense lawyers have been appointed for all five men.
The maximum penalty for a premeditated murder conviction is life in prison or the death penalty. Lewis-McChord spokesman Joseph Piek said decisions on whether to seek the death penalty normally are made after an Article 32 hearing.