Natural Hydrogen Gas (H₂) is producing a new golden rush worldwide due to its clean energetic features. The potential of natural hydrogen gas (H₂) in the southernmost regions of Brazil, specifically Rio Grande do Sul and Santa Catarina, remains largely unexplored. We found free H₂ occurrences identified in the intracratonic Mesozoic Paraná Basin, recognized in four formation tests performed in former exploratory wells. The data revealed H₂ concentrations ranging from 0.14% to 8.79%, albeit associated with noncommercial volumes of natural gas. These occurrences of H₂ exhibit a curious negative correlation with Helium (He), distinguishing it from many Eurasian occurrences associated with mantle sources. The Paraná Basin hosts the largest Brazilian coal reserves and organic-rich rocks. We posit that the hydrogen gas presence can be attributed to the maturation processes affecting mainly Rio Bonito, Taciba, and Ponta Grossa formations in this basin. Also, we identified hydrogen system elements in the rift-type Precambrian Camaquã Basin, which host potential source rocks, reservoirs, and seals. Until now, no H₂ measurements have been carried out in this basin. To solve this lack, it is fundamental to execute a systematic sampling survey; it will enable the identification of the potential of H₂ deposits in the Southernmost Brazilian region. This work lays the foundations for future research in the region, which is demanded to realize this economic potential.