The city-state, which has had comparatively mild COVID-19 outbreaks, has taken a tough line against people breaking virus rules, and there have been several cases of foreigners being punished.
Benjamin Glynn was arrested after footage of him not wearing a mask on a train in May went viral.
The 40-year-old subsequently harassed police sent to arrest him, and refused to wear a face-covering during a court appearance last month.
According to reports, Glynn delivered a rant in court — in which he described the proceedings as “preposterous” and “disgusting” — and said masks were not effective in preventing the spread of COVID-19.
This prompted the judge to order a psychiatric assessment, but Glynn was deemed fit enough for the case to continue.
On Wednesday, he was convicted for breaching COVID-19 rules, his behaviour towards police, and causing a public nuisance.
As he had already served two-thirds of his sentence on remand, Glynn was freed from prison Wednesday and will be deported, according to local newspaper the Straits Times.
Convicts in Singapore can be freed for good behaviour after serving two-thirds of a jail term.
In May, nine Britons were banned from working in Singapore after breaking coronavirus rules while partying on a yacht in Santa hats.
In June last year, four British men were similarly banned after going on a pub crawl in a breach of curbs. – AFP