This dataset contains experimental and numerical data as presented in the manuscript "Tunable superconducting diode effect in a topological nano-SQUID" by Ella Nikodem, Jakob Schluck, Max Geier, Michał Papaj, Henry F. Legg, Junya Feng, Mahasweta Bagchi, Liang Fu, and Yoichi Ando. The data presented in the experimental figures are given in csv files, where the physical quantities and their units are described in the headers. The simulation file and the script processing the result of this simulation generating the data shown in Figure 5b based on tight binding calculations can be found in the folder “tight binding model”. The python code generating supplememtary Figures S7 and S8 based on the phenomenological model can be found in the folder "phenomenological model".