Two hours from Bali’s tourist resorts, the Indonesian island of Sumba maintains a deeply entrenched system of hereditary slavery despite national laws banning the practice. In the rural village of Tenggedu, located in East Sumba, individuals known as “atas” continue to live in conditions akin to servitude, bound by tradition to serve their “maramba” masters without pay and often subjected to physical and sexual abuse.

Slavery has been outlawed in Indonesia for more than 160 years and is prohibited under the country’s 1945 constitution. However, the island’s caste system, rooted in the ancient marapu belief—a blend of animism and ancestor worship—divides society into three hierarchical groups: nobles or landowners called maramba, ordinary people known as kabihu, and slaves or servants referred to as atas. This structure has been preserved by Sumba’s geographical isolation some 2,000 kilometers east of Jakarta.

Kanisius Kanyali Hambarita, an ata living with his master Umbu Ana Rara in Tenggedu, described his position as an inherited tradition “that cannot be wiped away.” Despite his status, he is permitted modest economic activities such as working as a motorcycle taxi driver and cultivating a small plot of land. Umbu Ana acknowledged his ownership but asserted he treats Kanisius “like a member of the family.”

Yet accounts from other atas residents paint a grimmer picture. Some report regular beatings, forced labor from early childhood, and lack of recourse against abuse. One ata from a neighboring village recounted punishment for insufficient work and recalled encouraging his children to avoid the same fate.

Human rights observers estimate the number of slaves in East Sumba to be in the thousands, though exact figures remain uncertain. A social worker familiar with the area suggested approximately 1,700 slaves within a local population of 350,000, while others believe the number to be higher. Although forms of debt bondage and forced labor exist elsewhere in Indonesia, historians note that Sumba’s slavery is unique for its intergenerational transmission and shared living spaces between masters and slaves.

The maramba often justify their dominance through physical and sexual violence, practices reportedly normalized within the local community. Religious authorities and former officials acknowledge that female slaves are subject to the “right” of their masters, with sexual exploitation frequently deemed acceptable and not prosecuted as rape. Victims rarely come forward due to fear of retaliation and stigma.

In one case recorded by the Indonesian Child Protection Commission, an 18-year-old slave, raped since early adolescence by her master and his son, filed a complaint with police in Waingapu, East Sumba’s capital, in 2024. After two years, the investigation remains unresolved, highlighting challenges in addressing abuses within the caste system.

Local religious leaders and NGOs have intervened in some cases, providing protection and advocacy for victims of violence. However, officials acknowledge the difficulty of dismantling a system deeply woven into traditional beliefs and social structures. Gidion Mbilijora, former head of the East Sumba district and a slave owner himself, indicated the enduring strength of these customs despite ongoing human rights concerns.

While Indonesia boasts the world’s largest Muslim population and a diverse cultural landscape, the persistence of hereditary slavery in Sumba underscores the complexities of reconciling constitutional law with long-standing local traditions.