This dataset presents U-series bulk-rock results from two samples of large silicic eruptions from the Atitlán caldera in Guatemala, Central America. Sample one represents the supereruption known as Los Chocoyos (G17-23), while sample two corresponds to the preceding W-tephra eruption (G17-42). Analyses were conducted at the University of Wyoming using multi-collector inductively-coupled plasma mass spectrometry (MC-ICP-MS).