This dataset presents tephra layers, Ar-dates, age-model & stable isotope data from the >250 kyr-long Lake Chala sediment record, Kenya/Tanzania. The file is split into six tables: (1) metadata on the 30 tephra layers (29 visible tephra layers, one cryptotephra) studied to date, including sample and core codes, summary characteristics and ages; (2) summary of Ar-dating results on ten of the Lake Chala tephra layers; (3) the DCH_TephraAge Bayesian age model, which combines tephra, 210Pb and 14C age-estimates for the length of the core; (4) Raw single-grain WDS-EPMA results for all tephra layers studied in the DeepCHALLA sediment record; and (5) secondary standard data; (6) unpublished Diatom ?18O (‰ VSMOW), Bulk organic ?13C (‰), %C and Diatom d13C (‰) measurements for the full length of the core (given on a composite depth scale). These chronological data (Tables 1-5) are central to the reconstruction of palaeoclimate from a multi-proxy analyses of the Lake Chala sediment sequence and are included in publications by Baxter et al. (2023) and Martin-Jones et al. (2020, in review), for which references are given in the appropriate files. Stable isotope data (produced by Barker and Leng) remains unpublished at the time of upload. The data was generated by Catherine Martin-Jones, Christine Lane, Maarten Blaauw, Darren Mark, Melanie Leng and Phil Barker between 2017-2022. Much of the tephra data is published and references are provided.