The sentence, which was given by Copenhagen City Court after the man was convicted earlier this month, will now be appealed at the High Court, news agency Ritzau reports.
The accident occurred on May 6th last year, when the 25-year-old, who works in construction, crashed his jetski into a rented boat in Copenhagen Harbour.
International students Leah Bell, 18, from Louisiana and 21-year-old Linsey Malia of Massachusetts lost their lives in the accident.
During proceedings, the court was shown video footage of a group of jetskis travelling towards the central part of the harbour at high speeds just before the accident.
The prosecution had asked for a four-year prison sentence to be given.
"We are of the opinion that his sailing should be treated equally to reckless driving," deputy state prosecutor Ander Riisager of the Copenhagen State Prosecution Service told Ritzau.
The prosecution has decided to accept the punishments given to seven other jetski riders who were in the group that included the 25-year-old.
The seven were accused of endangering life by sailing recklessly in the harbour at the time of the accident, and could have faced months-long prison sentences.
But the court found them to have been proven only of breaching maritime safety laws, not the more serious charge of endangering life, resulting in their relatively mild sentences of fines of up to 11,700 kroner (1,570 euros).
Although the prosecution had argued for custodial sentences for the seven, that request will not be pursued.