Core RR0503-79JPC, located at 1165 m water depth in the Bay of Plenty, north of New Zealand, has been used to reconstruct past properties of intermediate water masses. Records from RR0503-79JPC cover the last deglaciation, from ~25–5 ka BP. Here we present the tephra depths and ages used to develop the age model for presentation of trace element (Mg/Ca and Li/Ca) and stable isotope (δ18O and δ13C) data. Several tephra layers have previously been identified within the sediment core and assigned radiocarbon ages (Shane et al., 2006; Lowe et al., 2013; Sikes et al., 2016). Here we update those ages with calibrated ages using SHCal20.