But James Monaghan, Niall Connolly and Martin McCauley were all sentenced on Tuesday for using false passports.
Monaghan received 44 months, McCauley received 36 months and Connolly 26 months in prison.
The three, who have been in Bogota since being detained in August 2001, may be expelled from the country.
They successfully persuaded a non-jury court they were not "urban terrorism trainers" and had been in Colombia as eco-tourists, hoping to monitor a fledgling peace process.
However, the prosecuting authorities in Colombia are to appeal the not guilty verdicts and their supporters fear this will delay their departure.
The trio were found not guilty of training Revolutionary Armed Forces of Colombia (FARC) rebels in the use of explosives.
In 2001, their arrest led to speculation that Irish republicans had formed links with the FARC.
The charge against them was that they were returning home after teaching the rebels the techniques of urban terrorism.
Their arrests made world headlines and shocked Washington, which has been ploughing millions of dollars in military aid to Colombia to back up the government's ongoing war against drugs barons.
The FARC is estimated to rake in about $600 million a year enabling the group to be one of the best equipped rebel organisations in the world.