Tropical forests are critical for maintaining the global carbon balance and mitigating climate change, yet their exchange of greenhouse gases with the atmosphere remains understudied, particularly for methane (CH 4 ) and nitrous oxide (N 2 O). This study reports on continuous measurements of CH 4 and N 2 O fluxes at the ecosystem and soil levels, respectively through eddy covariance and an automated chamber technique, in a wet tropical forest in French Guiana over a period of 26 months. We studied the magnitude of CH 4 and N 2 O fluxes and their drivers (climatic variables) during the driest and wettest seasons. Seasonal ecosystem fluxes showed near-zero net CH 4 uptake during the driest season and emissions during the wettest season that were larger in magnitude than the uptake. Meanwhile, N 2 O emissions were of similar magnitudes in both seasons. Upland soils within the footprint of the eddy covariance tower emitted N 2 O in both seasons, although these fluxes were particularly small. In contrast, upland soils were characterised by CH 4 uptake. Overall, seasonal ecosystem and soil CH 4 and N 2 O fluxes were partially explained by seasonal variations in soil water content, soil temperature and global radiation. The magnitude and sign of the net ecosystem fluxes of CH 4 and N 2 O were likely due to outgassing from aboveground biomass and the presence of seasonally flooded areas within the footprint of the eddy covariance system. Further studies of other ecosystem compartments in different forest habitats are needed to better understand the temporal variations in CH 4 and N 2 O fluxes in wet tropical forests.