In response to the pandemic that started in early 2020, prison systems around the world have adopted various strategies to prevent the spread of Covid-19 (coronavirus disease 2019). In Spain, the main strategy used by the State Penitentiary Administration against the pandemic has focused on the use of the “third degree” of prison or “semi-freedom” with telematic control (or electronic monitoring, as it is better known in the rest of the world). While in closed prisons the main measures to manage the pandemic have been focused on avoiding contact with outside, in open prisons inmates who could have introduced the virus into prison facilities due to their semi-freedom have been released and sent “home,” in order to prevent the spread of the virus. The author analyzes the data provided by the Spanish prison statistics during the pandemic, illustrating the evolution of the numbers of convicts classified in “open regime” and under electronic monitoring. At the same time, the author highlights some of the ethical and public security implications that might be posed by the quasi-massive release supported by the expansion in the use of open regime with telematic control, and some recommendations thereon are proposed. (COV-018)