<p>The expansion of oil palm farming in Southeast Asia has been premised on the mobilisation of both internal and transborder migrant labour. This paper examines labour relations on an oil palm plantation in Sabah, Malaysia, with a focus on the underexplored case of undocumented Filipino migrant workers from Palawan. Drawing on field-based research, we analyse the evolution of a migrant labour regime in light of debates on labour exploitation. We find that this labour regime is structured around three interrelated mechanisms: the mobilisation of a labour force primarily composed of undocumented migrant workers, the casualisation of labour relations, and the adoption of piece rate payments. Together, these mechanisms facilitate the extraction of surplus value by transferring risks and costs to workers, while undermining class-based solidarity through self-discipline, peer surveillance, and labour fragmentation. In response to debates about ‘free’ and ‘unfree’ labour, we argue that outsourcing, casualisation, and piece rate systems are not only markers of precarity but are deliberately structured to extract surplus value and inhibit migrant worker mobilisation. By situating Filipino migrants within the broader oil palm labour regime, this paper highlights the relational nature of labour regimes, demonstrating how undocumented migration and transnational mobility are central to sustaining contemporary agricultural production.</p>