The three, who have been in custody on the Continent for 28 months, have already been cleared in the Netherlands of the murder of two Australian tourists mistaken by the IRA for off-duty British soldiers.
Donna Maguire, Sean Hick and Paul Hughes are charged with the murder in Dortmund of Major Michael Dillon-Lee, the attempted murder of a policeman and another charge of attempted murder following a failed bomb attack on a Rhine Army barracks in Hanover.
The new trial, which is expected to last at least two years, is taking place in a Dusseldorf courthouse built to cope with Germany's Bader-Meinhof terrorist trials in the 1970s. Four months ago the IRA trial of Gerard Hanratty and Gerard McGeough ended in the same courtroom after almost two years.
Yesterday, Ms Maguire, 26, and Mr Hughes, 29, both from Newry, Co Down, and Mr Hick, 32, from Dublin, filed into the courtroom each flanked by two lawyers.
Ms Maguire faces another trial if acquitted. She is accused of murdering Corporal Steven Smith in July 1989 in a car bomb attack outside his Hanover home.
The chairman of the five judges in the present trial, Wolfgang Staffen, presided over the Hanratty-McGeough trial which ended in two-and-a-half years' jail for Hanratty for bombing Army bases in Germany in 1988. Hanratty, who served more than his jail term awaiting trial, was extradited to Belfast. McGeough was ordered to be extradited to the United States.
Yesterday, the Dusseldorf court prosecutor, reading out the charges, claimed the three in the dock were members of an IRA cell set up on the Continent in early 1990, living in Germany and the Netherlands under false identities. He said Mr Hick and Mr Hughes both denied the charges but Ms Maguire had said nothing.
The three accused acknowledged the judge when he read out their names, dates of birth and addresses. Each indicated they had nothing to say. The case was adjourned until 5 November and the three were returned to prison.