The island chain has faced upheavals since February
Maldives opposition Democratic Party on Saturday nominated veteran lawmaker Ibrahim "Ibu" Mohamed Solih as its presidential candidate a day after former president Mohamed Nasheed withdrew as the party's candidate for the September elections.
Solih will contest the poll against President Abdulla Yameen, who is bidding for a second five-year term amid continued instability in the Indian Ocean island chain.
After months of bickering, the Democratic Party (MDP) and the smaller opposition parties agreed to field common candidates, with the presidential candidate to have a running mate from Jumhooree Party.
Nasheed, Maldives first democratically-elected leader who lives in exile in Sri Lanka, on Friday said he had decided to relinquish his presidential ticket as the national election commission ruled him illegible to run.
Solih, first elected to parliament in 1994, is known for his calm composure.
"I will choose the way of negotiation and discussion," Solih told the party congress after wining the candidature.
"We will open the MDP manifesto to allow the joint opposition to make additions, but we will not allow MDP's values to be trampled. Together, we can do this."
The Maldives, home to 400,000 people and best known as a tropical paradise for tourists, has experienced political unrest since Nasheed was forced to quit amid a mutiny by police in 2012.
Nasheed, convicted of terrorism charges in 2015 and sentenced to 13 years in prison after a controversial and widely criticised trial, was the sole candidate when the MDP held a primary election in May.
President Yameen's administration has rejected a demand by a UN human rights watchdog to let Nasheed stand for the presidential election.
The opposition has accused the government of locking up most of the leaders who could effectively challenge Yameen's bid for re-election, a charge the government denies.
The island chain has faced upheavals since February, when Yameen imposed a state of emergency to annul a Supreme Court ruling that quashed the convictions of nine opposition leaders, including Nasheed.
During the 45-day emergency, Yameen's administration arrested former president Maumoon Abdul Gayoom, the chief justice, another Supreme Court judge and a Supreme Court administrator on charges of trying to overthrow the government.
In 2016, Nasheed was allowed to go on medical leave to Britain, where he received political asylum. Since last year, he has been in Sri Lanka, working to unite opposition parties to defeat Yameen.