In the last decades, Mt. Stromboli produced four vulcanian eruptions, in 2003 and 2007 and July and August 2019, recorded by INGV monitoring network. Specifically, last three events are studied through records from borehole strainmeters, which allow to infer details on source dynamics. These events are preceded by a slow strain buildup, starting several minutes before the paroxysms, which can be used in future for early warning. Eruptions consist of two or more strain pulses, with oscillations ranging from several seconds, as in 2007, to some minutes, as in 2019, and lasting from several minutes to 1 hr after the explosions. Plain Language Summary Sacks‐Evertson borehole dilatometers are a special kind of strainmeter, capable of recording volumetric strain changes. In the current manuscript, data recorded by such an instrument reveal that strain changes occurred several minutes before two paroxysmal events occurred in the summer of 2019 at Stromboli, an open‐conduit volcano located in Eolian Islands, Italy. A comparison of 2019 paroxysms has been made with previous eruptions at Stromboli volcano: Similarities among the explosions suggest a common source mechanism. Starting from these observations, a real‐time early warning system could be developed in the future, allowing Italian Civil Protection Department to set up automated (or semi‐automated) variable alert levels, which could trigger alarms accordingly. Such an early warning system could then be used to provide alerts for other similar open‐conduit volcanoes. Key Points Borehole dilatometers are widely used to monitor open‐ and closed‐conduits volcanoes, recording areal strain changes due to volcanic sources A dilatometer recorded strain changes minutes before eruptions onset for 2019 activity: Correlation with 2007 paroxysm suggests common source For the first time a comparison high‐frequency, high‐sensitivity strain data for the 2007 and both 2019 vulcanian explosions are presented