Data from journal article of Century-long records of sedimentary input on a Caribbean reef from coral Ba/Ca ratios: linking coral health and land use. FR12 Forereef collected at 16.13715 ˚N, 88.26015 ˚W BR06 Backreef collected at 16.14045 ˚N, 88.26015 132 ˚W Here we present century-long Ba/Ca records from two colonies of the coral Siderastrea siderea as a proxy for local riverine sediment flux to the southern Mesoamerican Barrier Reef System (MBRS). The two coral colonies have contrasting growth trends over the past century. The colony with a declining extension rate from the forereef of the MBRS, mainly receives riverine input from Honduras, whilst the coral from the backreef, which does not exhibit a decline in extension rate, primarily receives riverine input from the more sparsely populated regions of Belize. Ba/Ca increased (>70 %) through time in the forereef colony while the backreef colony showed little long-term increase in Ba/Ca over the last 100 years. Data were collected using laser ablation inductively coupled plasma mass spectrometry.