This study assessed soil organic carbon (SOC) stocks in three 15-year-old Ecuadorian cocoa plantations, focusing on the impact of varieties EET 95, EET 103 and EET 116. Twenty sampling points per plantation were established, stratifying by location (under-tree and in-row) and depth intervals (0-5, 5-10, 10-20 and 20-30 cm). Statistical significant differences in SOC concentration (%) and stock accumulation were determined by Analysis of Variance. Results revealed that EET 116 exhibited the highest SOC accumulation, reaching 41 t ha⁻¹ under trees and 54 t ha⁻¹ in-rows. EET 103 showed intermediate SOC stocks (37 t ha⁻¹ under trees, 47 t ha⁻¹ in-rows), while EET 95 had the lowest (36 t ha⁻¹ under trees and in-rows). Statistical analysis indicated no significant differences in SOC stocks between EET 95 and EET 103, nor between EET 103 and EET 116 under trees. However, EET 116 in-rows demonstrated significantly higher SOC stocks compared to all other treatments. Overall, these results emphasize the complex factors that influence the dynamics of SOC in cocoa plantations, highlighting the importance of considering varietal differences in carbon sequestration strategies for sustainable cocoa production.