PLOS ONE Undocumented: An examination of legal identity and education provision for children in Malaysia and 1990s and Kad Banci or Kad Hijau issued in the 2000s) and the rampant use of fraudulent identity documents served to confuse the documentation issue [52,56]. Recently, plans to consolidate the three identity documents under a “Sabah Temporary Pass” had been dropped following opposition from the local community [57,58]. Due to the alleged “Project IC”, a citizenship-for-votes scandal [59], the local Sabahan community tend to be suspicious with initiatives to provide identity documents or perceived citizenship entitlements like healthcare or education access to non-citizens. Our interviewees suggest that those of Filipino origin are among the most disadvantaged of the different subgroups in Sabah. Compared to Indonesian labour migrants, those of Filipino origin have been in Sabah for longer, are greater in numbers and tend to settle in urban areas rather than in oil palm estates. This stands in contrast with Indonesian labour migrants and their families, whose welfare is formally cared for by estate managers and have well-tended living conditions, with greater involvement of the Indonesian embassy. Those with Filipino origins are also more at risk of detention and deportation, which sometimes involve parent-child separation. In addition, the Philippine Consulate only has offices in Kuala Lumpur, but not in Sabah due to the frayed geopolitical situation, further exacerbating their risk of statelessness. (2) Indonesian labour migrants in the oil palm plantations and urban areas. Economic migration from Indonesia to Malaysia is not restricted to Sabah, but also in Sarawak and Peninsular Malaysia [60,61]. Under Malaysian Immigration Laws, low-wage economic migrants— commonly employed via the Employment Pass Category III (monthly salary below RM5000 and Temporary Employment Pass)—are not allowed to bring dependents, nor are they allowed to marry and establish new family units in Malaysia [62]. East Malaysia is the exception, as it is understood that migrant workers employed in estates (the majority of whom are Indonesian males) may bring their spouse and children if the estate can ensure the children’s education and the prevention of child labour in compliance with Roundtable Sustainable Palm Oil (RSPO) certification requirements [9,63]. It was estimated that there are between 30,000 to 60,000 children of Indonesian migrant workers in Sabah [9,64]. Interviewees suspect that there may be similar numbers of Indonesian children in Peninsular Malaysia, but we were unable to verify these figures. In Peninsular Malaysia, migrant workers are concentrated in urban areas, while in Sarawak, most reside in plantations. In Sabah, our study participants informed that half the Indonesian population may be found in plantations, while the other half are in urban areas, working at small farms or businesses. Mid- to large-sized oil palm estates collaborate with the Indonesian embassy to build and maintain learning centres within their estates. Otherwise, estates must provide children with transportation to the closest learning centres. Besides educational provision, it is also noteworthy that estates also provide housing, access to healthcare and amenities for migrant workers and their families. Study participants also informed that Indonesian children have less issue in documentation because of the active presence of the Indonesian Embassy in Sabah. NGOs with the support of employers, work with the Indonesian embassy to facilitate the issuance of birth certificates. (3) Stateless Bajau Laut nomadic tribes. The Bajau Laut—also known as Sama Dilaut, Pala’o or Sea Gypsies—reside in Sabah’s East Coast. The Bajau Laut are a seafaring community, who historically roamed between the islands off Sabah and the Sulu archipelago, that is part of present-day Philippines. Although they have been living along the coast of Sabah for generations, this mobile community are genuinely “stateless”, as they are not regarded as citizens of any country [65]. The Department of Statistics Malaysia estimates that there are 468,000 people from the Bajau ethnic group in Sabah. However, estimating the Bajau Laut population is challenging due to their semi-nomadic lifestyles [66]. PLOS ONE | https://doi.org/10.1371/journal.pone.0263404 February 2, 2022 10 / 26