The dataset consists of the world's longest fluvial dissolved organic carbon (DOC) record (1883-2014). The data have been measured at the outlet of the Thames basin, upstream of London (UK) and are reported monthly. The River Thames basin is a temperate, lowland, mineral soil-dominated catchment of 9,948 km2. Water colour data have been measured between 1883 and 1990, and DOC between 1990 and 2014. DOC until 1990 has been estimated through calibration between water colour and DOC for the period 1899-1905 when OC measurements were available. The fluvial DOC concentration shows an upward trend throughout the period. The data are presented as one table and one supporting file containing metadata and are summarised and presented in the Journal of Geophysical Research - Biogeosciences doi: 10.1002/2016JG003614. Full details about this dataset can be found at https://doi.org/10.5285/57943561-4587-4eb6-b14c-7adb90dc1dc8
