Opinion polls had forecast the coalition would fall short of a majority but a surge in support for the centre-right Progressive Party, which won five more seats than in 2017, pushed its total count to 37 seats in the 63-seat parliament Althingi, according to state broadcaster RUV.
The current government, which consists of Jakobsdottir's Left-Green Movement, the conservative Independence Party and the centrist-agrarian Progressive Party, said before the election that they would negotiate continued cooperation if they held their majority.
President Gudni Johannesson has yet to officially hand a mandate to the party that will be tasked with forming the next government.
The conservative Independence Party again became the biggest in parliament with nearly a quarter of votes despite losing one mandate.
The Left-Green Movement got six seats, down from nine in the 2017 election, although two parliamentarians left the party shortly after the last election.