Dale McLaughlan, 28, was jailed for four weeks after admitting arriving unlawfully on the island, having travelled from Whithorn in Scotland to Ramsey, a town that lies in the north of the Isle of Man.
Prosecutors said McLaughlan had expected the journey on Friday to take him 40 minutes, but it ended up taking four-and-a-half hours.
Under the Isle of Man's current laws, the only non-residents allowed to enter are those who have been given special permission.
McLaughlan had been granted permission previously to work as a roofer on the island for four weeks in September, having isolated for 14 days before meeting his girlfriend on a night out.
However, Douglas Courthouse heard how McLaughlan's subsequent applications to return had been rejected.
According to prosecutors, he bought the jet ski and set off on the journey of around 25 miles (40km).
When he arrived in Ramsey at about 1pm last Friday, McLaughlan then walked another 15 miles (25km) to his girlfriend's home in Douglas.
The court was told that his partner believed he had been on the island working for several weeks.
The next day, McLaughlan gave police her address as his own, before the couple went to two busy nightclubs that evening.
Police then carried out identification checks and arrested him on Sunday morning.
His defence lawyer said in court that he suffered from depression, and had not been coping without being able to see his girlfriend.
Sentencing, Deputy High Bailiff Christopher Arrowsmith said McLaughlan potentially put the community at risk by making a 'deliberate and intentional attempt to circumnavigate' the border restrictions, adding that the 'carefully planned' also put him 'at very real risk' of harm.
Guidelines on the website for the Isle of Man Government outlines a Borders Framework, which is the island's 'first line of defence from importing unacceptable levels of the virus'.
It says the government believes it is likely to need 'some form of border restrictions' for 'some time to come'.
Speaking after the hearing, a government spokesman said that, following an investigation, public health officials were 'satisfied' there was 'no wider risk to the public', according to the BBC.Featured Image Credit: PA