Oldoinyo Lengai in the North Tanzanian Divergence is the only active natrocarbonatite volcano world-wide and presents an important endmember magmatic system in a young rift segment of the East African Rift System. This volcano typically experiences long-duration episodes of natrocarbonatitic effusions with intermittent short-duration explosive eruptions. To better understand the role of the stress interactions and magma plumbing on the eruptions dynamics, this study aims to constrain the subsurface magmatic architecture of Oldoinyo Lengai, and a zone of ongoing seismicity and intrusive activity below the extinct 1 Ma-old Gelai shield volcano and active Naibor Soito monogenetic cone field. Waveform data are available from the GEOFON data centre, under network code 9J, and are embargoed until November 2025.