It serves nearly 300,000 Catholics in the municipalities of Bobonaro, Cova Lima, and Liquiçá, covering a total area of 3,142 km2 (1,213 square miles).

[1] After independence in 2002, the Holy See planned to create a third diocese centered in Same so that East Timor could form its own episcopal conference.

[2][3] However, these plans stalled around 2005 amidst ongoing changes by the government to the country's administrative subdivision boundaries.

[1][4][5][6] Amaral was consecrated on 24 April 2010 in Tasitolu, Dili, in a ceremony attended by Deputy Prime Minister José Luís Guterres, Supreme Court president Cláudio de Jesus Ximenes, attorney general Ana Pessoa Pinto, and other deputies, politicians, magistrates, diplomats, bishops, as well as thousands of priests, sisters, and laity.

[4][9] The parish church of Maliana became the diocese's new cathedral, and the government provided funding and a building for a temporary residence for the bishop.

[5][6] On 17 February 2019, a new episcopal palace and chancery building were inaugurated in a ceremony attended by bishops Amaral, Virgílio do Carmo da Silva of Dili, Basílio do Nascimento of Baucau, and former President Xanana Gusmão.

[10] As of 2022, the diocese has grown to nearly 300,000 Catholics, and now has 11 parishes and 65 missions served by 50 priests and 184 religious brothers and sisters.

For men, these include the Capuchins, Carmelites, Claretians, Divine Word Missionaries, and Jesuits.

[11][13] The diocese is also home to Don Bosco Technical School near Maliana, established in 2013 by the Salesians with funding from the Timorese and Spanish governments, which provides vocational training to 100+ boarding students.