Lightning is a natural hazard that significantly impacts human safety, infrastructures, and ecosystems. In recent decades, it has been monitored as a key indicator of severe weather and to understand climate change. This work examines the behaviour of lightning in Cuba from 2018 to 2022 using the Geostationary Lightning Mapper (GLM) onboard the Geostationary Operational Environmental Satellite 16 (GOES-16). We focused the analysis on the annual trends and spatial distribution of the keraunic level, i.e., the number of thunderstorm days and the total and cloud-to-ground lightning flash density. Our results showed a GLM efficiency of ~60-70% for detecting thunderstorms, which is aligned with previous studies using surface weather station data. In addition, we obtained an equation to determine the relationship between the number of thunderstorm days and the cloud-to-ground lightning flash density per year over an area of 1 km². Overall, this research resulted in the first keraunic level map developed for Cuba, using geostationary satellite data, and it provided the first maps of the total and cloud-to-ground lightning flash density. Although the keraunic level values were underestimated compared with reports from weather stations, they captured the characteristic climatic behaviour of thunderstorms in the study area. In summary, our findings demonstrate the feasibility of using GLM data to study thunderstorms and lightning activity in Cuba.