Bollettino Sismico Italiano, I quadrimestre 2021, version 1.0 contains 5282 earthquake locations in the Italian region and in the border region in the time frame between 01-01-2021 and 30-04-2021. Data used have been recorded by the National Seismic Network, operated by Istituto Nazionale di Geofisica e Vulcanologia (INGV) and regional and international networks operated by several providers. The BSI analysts revised event with M>=1.5 (1928), 42 of them whit a M>=3.5; to locate the earthquakes we used 639 stations which contributed to the locations with 43250 P phases and 28365 S phases. The Bollettino Sismico Italiano is available in Quakeml format and is described on a 4 months basis by a pdf document, but is also available in the ISIDe data-base for the period 1985-today. Both Quakeml files and pdf document are available at CNT webpage (http://terremoti.ingv.it/bsi).