The active Barren Island volcano and the Pleistocene Narcondam ­volcano, located ∼140 km to the North, are the only two subaerially exposed Andaman arc volcanoes, which rise from the 1,000 to 2,300 m deep seafloor of the Andaman Sea, and are associated with the subduction of the Indian plate beneath the Burma plate. Lavas at Barren Island range in composition from basalt to andesite while lavas from Narcondam volcano range from andesite to silicic andesite/dacite. Similarities in the geochemistry of both lava suites include strong and comparable depletions in Nb and Ta (K2O/Nb ∼0.7; Ba/Nb 130–250), low MORB-like Nb/Zr (0.01–0.03) and nearly constant U/Th (0.15–0.22). These characteristics suggest a genetic link between both magma suites, but there are geochemical differences such as elevated trace element abundances and ratios in Narcondam lavas compared to Barren Island lavas. These include elevated Ba, Rb, and U concentrations and higher Ba/Zr and Nb/Zr. Additionally, isotopic ratios of Barren Island lavas are 87Sr/86Sr ∼0.7039–0.7041, 143Nd/144Nd ∼0.51285–0.51296, and 206Pb/204Pb ∼18.063–18.309. For Narcondam, isotope ratios are 87Sr/86Sr > 0.705, 143Nd/144Nd ∼0.51270, and 206Pb/204Pb ∼18.565–18.617. Additional geochemical parameters (e.g., Sr/Y, Zr/Y, Th/La, U/La, Ba/La) of Narcondam lavas positively correlate with increasing SiO2 but are anchored at the mafic end within compositions observed at Barren Island volcano. Similarities in the geochemistry of both lava suites, of which some (e.g. high Th/Nb) stand out in comparison to other intra-oceanic arc systems, almost certainly originate early during the generation of these magmas, most-likely in the source of magmas that do not change subsequently. On the other hand, generally more incompatible element enriched silicic Narcondam magmas are best explained by amphibole-dominated fractionation of a Barren Island-type basalt. Such a scenario would be consistent with an increase of Sr/Y correlated with increased silica and the presence of greater amphibole in samples with higher Sr/Y. The shift in isotopic values from typical Barren Island values to those of Narcondam samples is likely caused by assimilation of extended continental crust and/or sediments from the fan associated with the Irrawaddy Delta at the Myanmar continental margin.