Mauritius will hold legislative elections on November 10, the presidency announced on Friday, just a day after Port Louis sealed a landmark deal to regain sovereignty over a chain of islands from Britain.
Parliament was to be dissolved immediately, President Prithvirajsing Roopun's office said, with candidates to be nominated by October 22.
A five-year deadline meant parliament was due to be dissolved by late November in any case.
But the announcement came just after Mauritius secured a long-awaited deal with Britain on Thursday to regain control of the Chagos Islands.
For years, Britain had resisted international pressure to hand back the remote Indian Ocean archipelago because it maintains a military base jointly with the United States on the biggest island, Diego Garcia.
Under the deal, Britain will retain a lease to keep the military base open for an "initial" 99 years.
Mauritius is a prosperous and stable democracy in a sometimes volatile neighbourhood.
It is predominantly Hindu but with sizeable Muslim and Chinese constituencies, as well as groups from Creole and European backgrounds.
Prime Minister Pravind Jugnauth inherited his position in 2017 on the death of his father, Anerood Jugnauth, as head of the centre-right Morisian Alliance.
He confirmed his standing with victory in the 2019 election, when his coalition won 42 of 70 seats.
Britain decided in 1965 to separate the Chagos islands from Mauritius and set up a military base there, which it later developed alongside the United States.
The base is home US long-range bombers and ships and was used during the wars in Afghanistan and Iraq.
Thursday's deal was hailed by US President Joe Biden as a "historic agreement". Biden said the base "plays a vital role in national, regional, and global security".
"For the first time in more than 50 years, the status of the base will be undisputed and legally secure," the UK foreign ministry added.
Jugnauth said Thursday that the deal showed how a small country can "win justice against major powers".
"Today, 56 years after our independence, our decolonisation is complete. Now our national anthem can sound out even louder across our territory," he said.
Britain evicted thousands of Chagos islanders when it built the base in the 1970s.
The new treaty, which has yet to be finalised, could pave the way for their return, though that is considered unlikely given the current lack of any permanent population.
