The Southeast Asian region, at the convergence of the Eurasia, Indian-Australia, and Pacific plates, is a crucial area for studying Earth's tectonics. This region is surrounded by subduction zones, where these significant plates are convergent from the west, south and east to form a complicated, curved-shape subduction system. This tectonic setting makes Southeast Asia an important natural laboratory for understanding the interactions between plates, subduction processes, and mantle convection. Ongoing oceanic subduction has built extensive volcanic arcs characterized by active volcanoes and complex surface structures, contributing to the region’s high seismic and magmatic activity. However, significant knowledge gaps remain regarding the subsurface structure, from the shallow crust to the deep mantle, particularly beneath ocean basins, as well as the impact of subducted materials on island arc and intraplate magmatic activities. An integrated approach combining geology, geochemistry, geophysics, and numerical modelling is essential for further understanding Southeast Asia's dynamic processes and the influence of past and present tectonic interactions on the region’s geology and climate.