In summer 2018 the energy company St1 carried out its first stimulation of deep geothermal wells in Otaniemi, Espoo, in the Helsinki metropolitan area, southern Finland. The Institute of Seismology of University of Helsinki (ISUH) monitored the induced seismicity during the stimulation, and also months before and after it. This dataset consists of seismic waveforms of 254 induced earthquakes that occurred between 5 June 2018 to 8 August 2018, with local magnitudes between 0.5 and 1.8. Waveform, location and timing data have been produced at ISUH using seismic stations of the Finnish National Seismic Network (doi: 10.14470/UR044600), the temporary HEL broadband network, the temporary borehole network of St1 (doi: 10.1785/0220190253), and a pool of lightweight mobile seismic instruments operated by ISUH (GIPP data cubes, doi: 10.5880/GIPP.201802.1). The deployment is described in Hillers et al., 2020, The 2018 Geothermal Reservoir Stimulation in Espoo/Helsinki, Southern Finland: Seismic Network Anatomy and Data Features, doi:10.1785/0220190253. Event data, event metadata, and station metadata are provided in distinct directories. For event data, each event is assigned a subdirectory. Data formats follow generally accepted seismological standards.