The data comprise measurements of the 'soluble', 'chemically exchangeable' and 'isotopically exchangeable' U concentrations in a diverse set of soils following experimental addition of UO22+ and incubation in the laboratory under controlled temperature conditions for ca. 1.7 years. The long term behaviour of U in aerobic soils was studied by conducting a laboratory-based experiment in which a set of twenty topsoils from central England with contrasting properties (e.g. pH, organic matter content, land use) were contaminated with a solution containing UO22+ in soluble form and incubated in the dark, in a moist but aerobic condition, at a temperature of 10 deg C for 619 days. The transformations of U in each soil microcosm were periodically monitored by means of soil extractions conducted on subsamples of incubated soils. The resulting dataset enabled quantification of the kinetics of UO22+ transformations in aerobic soils and the relationships with soil properties and land uses (arable, grassland and moorland/woodland). The dataset will be useful in developing models of long-term U bioavailability in aerobic soils under temperate conditions. Full details about this dataset can be found at https://doi.org/10.5285/0d8b2aea-574c-4cff-a8bd-17115a0b90fc
