The Main St church was bought by the Ashburton Muslim Association at auction in May.
The imam (leader) of the Mataura Masjid (mosque), Zamberi Bin Matyunus, a New Zealand citizen originally from Malaysia, lives in Mataura with his family.
Its members came from various walks of life and included farm workers, electricians, doctors and workers in the meat-processing industry.
Mr Matyunus said once people in the wider Muslim community learned about the association's plans to buy the church, donations came flooding in, and the association was able to buy it.
He had studied the Koran, the central religious text of Islam, in countries around the globe, including India, the United Kingdom, United States and many Arab countries.
The mosque is open to the whole community.
"It doesn't matter your religion. We're not fanatics."
Muslims pray five times a day.
The mosque is one of seven in the South Island.
The next-nearest one is in Invercargill.
The Rev Gary Griffith-Smith, of Gore's Holy Trinity Anglican Church, said the Mataura church had been part of the Gore and district parish before it was closed three years ago because of declining attendance and ongoing maintenance costs.
"We were down to about three people."
Those people attended services in Gore instead.
