Magnetotelluric (MT) time series including the September 2017 magnetic storm at 7 sites in the Scottish Highlands collected by Fiona Simpson (University of Southampton) and Karsten Bahr (University of Göttingen) using Göttingen RAP dataloggers, Magson fluxgate magnetometers and Filloux-type electrodes. Data acquisition methodology is described in F. Simpson and K. Bahr, 2005. Practical Magnetotellurics, Cambridge University Press, London pp. 254, 2005, ISBN: 9781108462556, DOI: 10.1017/CBO9780511614095 This dataset is described in: F. Simpson and K. Bahr, 2020a. Nowcasting and validating Earth’s electric field response to extreme space weather events using magnetotelluric data: application to the September 2017 geomagnetic storm and comparison to observed and modelled fields in Scotland, Space Weather, accepted, doi pending. F. Simpson and K. Bahr, 2020b. Estimating the electric field response to the Halloween 2003 and September 2017 magnetic storms across Scotland using observed geomagnetic fields, magnetotelluric impedances and perturbation tensors, Journal of Space Weather and Space Climate, accepted, doi pending.