Established in 1979 from the Diocese of Kollam, it covers southern Kerala and parts of Tamil Nadu and includes the ancient Thiruvithamcode Arappally.
Counts above reflect Orthodox-held institutions only; churches, chapels, and other properties currently under schismatic occupation are catalogued separately below and are not included in these totals.
The region includes the Thiruvithamcode Arappally, said to have been established by St. Thomas the Apostle in 63 CE, and a historic Tamil mission church at Palavalai, Kanyakumari.
The diocese was established on 1 January 1979 on the recommendation of the Malankara Syrian Christian Managing Committee to divide the expanding Diocese of Kollam, and began with 94 parishes. Baselios Marthoma Mathews I administered it as Malankara Metropolitan, with Geevarghese Mar Dioscoros as Assistant Metropolitan until his consecration as first Diocesan Metropolitan in 1981. Under him the Orthodox Church Centre at Ulloor was established as the bishop's house in 1986, and in 1991 the Charitable and Educational Society was founded to manage institutions such as the Mar Dioscorus College of Pharmacy. Mathews Mar Epiphanios and Dr. Gabriel Mar Gregorios later served as Metropolitans.
In 2010, to improve administration, the diocese was divided to create the Diocese of Kottarakkara–Punalur. It covers the southern edge of Kollam district, Thiruvananthapuram district, Kanyakumari district and parts of Tirunelveli district. It is headquartered at the Orthodox Church Centre, Ulloor (now moved to Powdikonam Mother Mary Ashram), with St. George Orthodox Cathedral, Palayam, as its primary cathedral.
6 districts, listed alphabetically.