Many Indonesian migrant workers' children in Peninsular Malaysia cannot enter national schools because their parents lack enrolment documents. Studies of community education for them have centered on secular, state-linked provision. This article examines a contrasting case: the At-Tanzil network of Qur'anic learning studios (sanggar bimbingan) in Selangor and Kuala Lumpur, founded and run by IKABA and IMABA, alumni associations of the Madurese Islamic boarding school Pesantren Mambaul Ulum Bata-Bata. This qualitative single-case study with embedded units draws on interviews with a coordinator, five managers, and ten teachers, field observations, and a documentary corpus. Bernstein's pedagogic device and Levitt and Glick Schiller's transnational social fields frame the analysis, separating institutional transmission, pedagogical enactment, and learning outcome. Evidence covers transmission and enactment, not learning outcomes. The network reproduces the pesantren's method across the border through alumni-mediated organization rather than direct control. Centralized coordination and recruitment through sanad, the chain of transmission, make sanad both epistemic authority and transnational connection. The central contribution, selective fidelity, describes how institutional actors protect a pedagogical core (the per-juz method, session structure, and advancement rules) and license adaptation in the organization and linguistic mediation of learning: multigrade grouping, compressed time, and pronunciation across Malay, Indonesian, and Arabic. Teachers' claims to represent the pesantren, nation, and religion conflict rather than align, and their transnational participation intersects with legal and material precarity. It yields propositions for comparative testing, not a validated model