The data consists of Fe-isotope ratio measurements, expressed in permil notation (δ57Fe) relative to the international standard IRMM-014 following standard practise. The measurements are of bulk rock samples and the sample set consisted of a suite of well-characterized basalts and picrites from three periods in the evolution of the Galápagos plume, from the approximately 70- to 90-Ma plume head [Tortugal, Curaçao (Lesser Antilles), and Gorgona Island (Colombia)], 60- to 70-Ma head-tail transitional accreted terranes [Quepos (Costa Rica) and Azuero Peninsula (Panama)], and modern (<2 Ma) steady-state plume. The samples were provided by collaborators Esteban Gazel (Central American samples) and Dennis Geist (Galapagos) in powder form. Original data on the samples can be found in the following references: D. J. Geist, T. R. Naumann, J. J. Standish, M. D. Kurz, K. S. Harpp, W. M. White, D. J. Fornari, Wolf Volcano, Galápagos Archipelago: Melting and magmatic evolution at the margins of a mantle plume. J. Petrol. 46, 2197–2224 (2005). M. D. Kurz, J. Curtice, D. Fornari, D. J. Geist, M. Moreira, Primitive neon from the center of the Galápagos hotspot. Earth Planet. Sci. Lett. 286, 23–34 (2009). J. Trela, E. Gazel, A. V. Sobolev, L. Moore, M. Bizimis, B. Jicha, V. G. Batanova, The hottest lavas of the Phanerozoic and the survival of deep Archaean reservoirs. Nat. Geoscience 10, 451–456 (2017). J. Trela, C. Vidito, E. Gazel, C. Herzberg, C. Class, W. Whalen, B. Jicha, M. Bizimis, G. E. Alvarado, Recycled crust in the Galápagos Plume source at 70 Ma: Implications for plume evolution. Earth Planet. Sci. Lett. 425, 268–277 (2015). Iron separation and isotope measurements were performed at the Department of Earth Sciences, University of Cambridge following established procedures such as those described in the following papers: H. M. Williams, M. Bizimis, Iron isotope tracing of mantle heterogeneity within the source regions of oceanic basalts. Earth Planet. Sci. Lett. 404, 396–407 (2014). C. R. Soderman, S. Matthews, O. Shorttle, M. G. Jackson, S. Ruttor, O. Nebel, S. Turner, C. Beier, M.-A. Millet, E. Widom, M. Humayan, H. M. Williams, Heavy δ57Fe in ocean island basalts: A non-unique signature of processes and source lithologies in the mantle. Geochim. Cosmochim. Acta 292, 309–332 (2021). Measurements were made on a Neptune Plus multicollector inductively coupled plasma mass spectrometer (MC-ICPMS) in wet plasma, with typical 2 SEs on multiple δ57/54Fe measurements of the same sample better than 0.02‰ and measurements of reference materials in agreement with accepted values. Data table S1 gives the measured Fe isotope data, along with a compilation of selected literature major and trace element used in this study. Data table S2 gives the measured Fe isotope data for the geological reference materials used during analytical sessions. Data table S3 gives the range of calculated primary Fe isotope compositions for each locality. For more information see published paper, Caroline R. Soderman et al. ,The evolution of the Galápagos mantle plume. Sci. Adv.9,eadd5030(2023).DOI:10.1126/sciadv.add5030