The soldiers from a regiment based in Andalusia have been charged over alleged torture at the Spanish military base in Diwaniya, Iraq on an "unspecified date" in either January or February 2004, Spain's El País newspaper reports.
The accused soldiers include a captain, currently working for Spain's secret service agency the CNI, two corporals — one now with the Spanish Legion and the other a Guardia Civil officer — and two former Legionnaires who are now also Guardia Civil employees.
Under Spain's military penal code the men face from 10 to 25 years in prison.
The case broke after El País in 2013 released video footage of three soldiers brutally kicking two prisoners, one since deceased, who were lying on the floor of their cell.
Two other soldiers stood in the doorway watching while a sixth filmed the scene in what the military later said "could be" the Spanish military base of Diwaniya, Iraq.
In April, a soldier testified on the matter, explaining the two prisoners filmed had entered the base, leading a donkey loaded up with explosives. "They were curled up against the wall, frightened like puppies," he said of their state after the attack.
A charge sheet for the five soldiers now describes the 25-second attack in minute detail. After cursing one of the prisoners, a corporal punched him. One of the legionnaires then kicked the detainees at least 15 times in succession.
After that legionnaire moved away he then returned and kicked the prisoners twice more before giving one final kick. A second legionnaire then kicked the detainees at least five times ,and a third soldier kicked them nine times, to make a total of at least 32 kicks.
"The pain of the Iraqi prisoners can be heard (in the video)," the charge sheet reads.
"Although they were able to, none of (the soldiers) present acted to stop the attacks" it adds.
"In the same way, none of them objected or complained to a senior officer. Instead they participated in the humiliation with their supporting presence and their laughs."
The army has said no higher officers were aware of the incidents and "didn't even suspect that prisoners were being mistreated".
They said the case was an isolated one and shouldn't be seen as a reflection on the work of the 130,000 Spanish soldiers who had participated in international missions in the last two years.
The captain involved in the incident has been locked up in Madrid's Alcalá de Henares military prison since July while the legionnaire who filmed the incident has been found not guilty of any crime after collaborating with authorities.