Dipterocarp forests are common in the northern plains of Cambodia, but litt le is known about the fi sh that occupy seasonal wetlands in these. With pressures increasing on Cambodian wetland resources, more information is needed on the value of small wetlands. We describe fish assemblages in seasonal wetlands in Kulen Promtep Wildlife Sanctuary based on sampling completed during the early-wet, wet and dry seasons in 2015–2016. A total of 1,895 fish were captured, representing 53 species in 17 families. Fish assemblages were most diverse during the wet season according to the Shannon-Weiner index and species richness. We were not able to identify distinct seasonal assemblages using non-metric multi-dimensional scaling, which may have been due to diﬀ erences in sampling eﬀ ort between seasons. There was no signiﬁ cant correlation between log-transformed wetland area and diversity measures, although correlations between maximum water depth and diversity were signiﬁ cant and positive. Binomial generalized linear models were used to examine whether season, connectivity to permanent water bodies (categorical) and maximum water depth were related to presence of the ﬁ ve most common species. None of the models revealed signiﬁ cant relationships, although depth was in the best ﬁt model for each species. These results indicate that water depth may be important in inﬂuencing the diversity of ﬁ sh assemblages and presence of common species in seasonal wetlands. Our pilot of rapid sampling methods can inform protocols for assessing small wetlands in the region and we provide recommendations for improving these methods.