Abstract The islands of the Maritime Continent are highly vulnerable to sea‐level rise driven by barystatic, sterodynamic, and vertical land motion (VLM) processes. While tectonics is known to affect relative sea‐level through VLM, its influence on long‐term geocentric sea level (GSL) through crustal deformation and gravity field perturbations remains poorly constrained. A process decomposition of satellite‐observed GSL change (1993–2021) reveals a significant residual trend along the Sumatra–Andaman subduction zone that cannot be explained by known oceanographic processes. This signal coincides with GRACE‐derived long‐term geoid change and the 2004 Indian Ocean earthquake rupture zone, indicating that tectonic deformation may imprint a measurable signal on long‐term GSL change. Confirming this tectonic origin, given the possible deep ocean sterodynamic contributions, requires sustained ocean in situ observations and geophysical modeling.