The conversion of Brazilian tropical forests into pastureland was a complex process, potentially harmful to the environment, heightened by degraded grazing systems that did not ensure sustainability and affected the ecosystem resilience. This study was conducted to determine the long-term changes in soil C stocks in native forest (FOR) converted to pasture-based dairy systems (continuous grazing system with low stocking rate-CLS; rotational grazing system with high stocking rate-RHS). Soil samples were analyzed for texture, C, organic matter (OM), bulk density (BD), C stock, and carbon accumulation rates (CAR) in 0-to- 5-, 5-to-10-, 10-to-20-, 20-to-30-, 30-to-40-, 40-to-60-, 60-to-80-, and 80-to-100-cm depths in six trenches. Bulk density was higher in RHS compared with CLS and FOR in most of the soil layers. In the 0-to-5cm layer, C and OM were greater in CLS. Carbon contents were similar in RHS and FOR, whereas OM was higher in FOR. Intensification increased BD, reduced OM, and did not affect C content in the 0-to-5 cm layer. For all treatments, C stock and CAR were higher in the 0-to-100 cm (136.73 Mg ha −1 and 0.4252 Mg ha −1 yr −1 ) than the 0-to-30 cm (61.79 Mg ha −1 and 0.0447 Mg ha −1 yr −1 ) layer. The soil C stock remained equal for both pastureland and presented a positive CAR in relation to the forest, working as C sinks. The RHS presented the greatest forage yield, carrying capacity and milk yield. This management resulted in a land-saving effect of 2.7 ha for each hectare of high intensified pasture. How to cite this article: Oliveira PPA, Rodrigues PHM, Praes MFFM, et al. Soil carbon dynamics in Brazilian Atlantic forest converted into pasture-based dairy production systems.