These processed data and provisional codes were created to investigate seismic velocity changes associated with the collapse of Kīlauea caldera during its 2018 eruption. Primary data (i.e., seismic waveforms) are hosted at the Incorporated Research Institutions for Seismology (IRIS; https://www.iris.edu/) and are ingested by the codes included here to reproduce the data analyzed in Hotovec-Ellis et al., 'Earthquake-derived seismic velocity changes during the 2018 caldera collapse of Kīlauea volcano.' The included code ('cwire' short for Coda Wave Interferometry with Repeating Earthquakes) takes a catalog of earthquakes clustered by waveform similarity (e.g., REDPy, https://github.com/ahotovec/REDPy/) and processes the coda for each pair of earthquakes within each cluster for changes in seismic velocity. Specifically, it finds the optimal time stretching factor to either expand or condense one earthquake's coda waveform to match the other, with that stretching factor equal to the relative change in seismic velocity (dv/v). It then takes those pairwise measurements and uses damped least-squares inversion to find the continuous time series that fits the pairwise measurements and writes them to the 'out' directory; results from runs described by the included configuration files are included in this directory for validation as part of this data release. The resulting time series can then be compared across the local seismic network and with other time series such as deformation. All data are stored in HDF5 database files (*.h5) created in the working directory. See README.txt for further documentation.