CCTV footage outside a top-end hotel in Naples shows the British man, dressed in shorts and a T-shirt, stepping out of a taxi in the southern Italian city. He is then approached by the thief who snatches the tourist's watch off his wrist, leaps over the hotel's hedge and onto the moped of an accomplice.
The stolen watch was by Swiss brand Hublot and valued at €35,000 according to Italian media.
Despite the speed of the carefully-crafted theft, police were able to catch up with the robber thanks to the video footage. He was arrested in his home, where they also found the helmet and clothes he wore to carry out the mugging.
The thief was taken to prison while police are still trying to identify his accomplice and reclaim the stolen watch, Tgcom24 reported.
The victim and Italian authorities did not contact the British embassy for assistance, a spokesman told The Local.
Britain's foreign ministry does not specifically refer to Naples' city centre when advising travellers of safety and security in Italy. It instead warns generally of higher levels of petty crime in big city centres, telling tourists to look out for coordinated gangs of thieves.