The timescales of element transfer at volcanic arcs provide important insights into magma generation, movement and storage beneath destructive margin volcanoes. Here we present major, trace and Sr-, Nd- and U-series isotope data on <200 ka old samples from Santorini in the Aegean volcanic arc as a case study of a hazardous destructive margin volcano. Samples range from low-K calc-alkaline basalts to high-K rhyolites, are enriched in light rare earth elements and fluid mobile trace elements, and have negative Ta, Nb and Ti anomalies characteristic of arc magmatism. 87Sr/86Sr ratios range from 0.7035 to 0.7054 and are negatively correlated with 143Nd/144Nd ratios, ranging from 0.51285 to 0.51263. Lavas from the second eruptive cycle (~ 180 ka-~3.6 ka) are in U-Th radioactive equilibrium, and a whole-rock, plagioclase, magnetite U-Th mineral isochron from a 67±9 ka dacite yields an age of 85 (+22/-19) ka (1σ). Samples from the Kameni islands (46 AD-1950) show small but significant uranium excesses, with (238U/232Th) = 0.91-1.04 and (230Th/232Th) = 0.91-0.97, suggesting that the time since U-Th differentiation is ≤ 147 (+27/-21) ky (1σ). A U-Th mineral isochron from the 1940 Kameni dacite yields an age indistinguishable from its eruption age. The Kameni samples show variable Ra depletion, with (226Ra/230Th) = 0.92-0.99. The range in Sr and Nd isotope data reflects progressive crustal assimilation. The combined trace element and isotope data are consistent with a three-component source model involving mantle wedge, sediment melts and slab-derived fluids. While initial 238U-excesses in the second eruptive cycle have decayed, implying slab-derived fluid addition > 180 ky prior to eruption, for the Kameni lavas fluid addition to the wedge is ≤ 150 ky. U-Th mineral isochrons indicate that crystal residence times in the subvolcanic plumbing system are short. Fractional crystallisation less than ~ 1 ky prior to eruption of the Kameni dacites is suggested by (226Ra/230Th) < 1. The combined data imply that timescales of magmatic differentiation in crustal reservoirs are short, that transfer time of the slab-fluid signature through the mantle wedge varies through time.