This repository contains the data and software used in the article “Characterisation of the plumbing system beneath Askja Caldera, Iceland, revealed by microgravity and deformation data during uplift between 2022 and 2023”, submitted to JGR: Solid Earth. The study investigates the compressibility of the mush zone where new magma was intruded during the 2022–2023 uplift period. To achieve this, we jointly inverted gravity and deformation data to estimate the volume and mass change of the intruded magma, allowing us to infer both the intrusion density and the mush compressibility. We used GNSS time series operated by the Icelandic Meteorological Office (IMO). Microgravity data was taken in August 2022 and August 2023. The microgravity data taken in August 2022 is originally available in (Koymans et al., 2023; https://doi.org/10.4121/912b666b-95c0-4f93-9485-e98256517991.v1), but we have also upload the data here. We also present the LOS velocities after corrections and the decomposed velocities into east-west and near-vertical component. Volume and mass changes of the magma body beneath Askja Caldera were estimated using MATLAB code developed by Nikkhoo and Rivalta (2023). This code was integrated into the GBIS software (Geodetic Bayesian Inversion Software; Bagnardi and Hooper, 2018) to enable joint inversion of deformation and gravity data. The original version of GBIS is available at https://comet.nerc.ac.uk/geodetic-bayesian-inversion-software-gbis/. The modified version of GBIS used in this study is included in this repository.