Explosive volcanic eruptions pose major hazards, yet reconstructing their frequency is challenging on small, weathered volcanic islands. This study explores massive corals as novel archives of volcanic activity, as tephra deposition alters seawater chemistry and can be recorded in coral skeletons. Skeletal cores from Siderastrea siderea and Diploria strigosacollected in Barbados and St. Vincent (including during the 2020–21 La Soufrière eruption) were analysed using micro-CT and LA-ICP-MS. A new method quantified skeletal porosity to reconstruct growth timelines, showing summer-driven calcification peaks and long-term increases in porosity linked to ocean warming and acidification. The eruption produced distinct porosity and geochemical anomalies, strongest near St. Vincent due to higher tephra input. Elemental ratios (e.g., Mn/Ca, La/Ca) tracked sediment influx and eruption phases, with prolonged post-eruption enrichment. Results demonstrate that coral skeletal records sensitively capture volcanic disturbances, offering a high-resolution tool for reconstructing past eruptions in marine settings.