Background: Patient safety is a public health problem worldwide. In situ simulation (ISS) arises as a learning strategy that allows health professionals to immerse themselves in a real environment without endangering the patients until they have learned the skills needed, thus increasing the quality of care. This systematic review aimed to verify the efficacy of the use of in situ simulation as a method that will allow health professionals to increase patient safety in Intensive Care Units after the situation experienced during the pandemic caused by the COVID-19 virus. Methods: Seven studies were reviewed using the PRISMA methodology for systematic reviews. The CASPe guide was used to assess the quality of the manuscripts. Results: The main topics that emerged from this review in relation to in situ simulation were as follows: looking at aspects such as patient self-perception of safety, adverse events, interprofessional communication and health system organization in relation to in situ simulation. Conclusions: The adequate implementation of in situ simulation after the COVID-19 pandemic in ICU services is shown to be an efficient and effective strategy to promote improvement in the attitudes on a culture of safety and teamwork of professionals.