The 32-year-old Irishman was charged by Italian police after being spotted using a sharp object to deface the 1,950-year-old landmark.
Security staff at the Colosseum Archaeological Park saw the unnamed man etching his name into the stone on the first level and notified the carabinieri, reports Italian newspaper La Repubblica.
Italian police were called to the scene and reportedly charged the tourist with damaging assets of historical and cultural importance.
It’s not the first time tourists have left their mark on the amphitheatre.
In March 2015, two American women were also caught carving their names into the Colosseum.
Aged 21 and 25, the two Californians strayed from their tour group to scratch their initials into a wall using a coin, before taking a selfie to commemorate the vandalism.
They too were caught and charged by Italian police.
“There’s a difference in perception,” a spokesman for the Special Superintendency for the Archaeological Heritage of Rome said at the time.
“Museums are treated like churches, sacred places where there are things of great value. Whereas the Colosseum is an incomplete building which has already been robbed.”
And in July the same year, a 22-year-old Lebanese tourist was charged for the same offence.
Security guards caught the woman as she used a coin to carve ‘HA’ into a pillar at the tourist attraction.