OpenRainER is an open-source dataset containing two years of data (2021 and 2022) from both conventional sensors (CS), such as radars and rain gauges from Arpae-SIMC, and opportunistic sensors (OS), in this case Commercial Microwave Links (CML) from the Lepida ScpA (Bologna, IT) network. Following the OpenSense community recommendations, the dataset is released under a Creative Commons license (CC-BY 4.0). This will promote scientific research about OS and encourage the exploitation of CML as a source for rainfall data. OpenRainER offers the opportunity to serve as benchmark dataset for CML retrieval algorithms and validation techniques over long periods and complex terrain.