Southeast Asian caves contain a plethora of ‘breccia’, or lithified conglomerate formed by carbonate-rich seeping water. These breccia deposits contain a wealth of valuable evidence to reconstruct the environmental conditions experienced by hominins dispersing through the region. Stable isotope analysis is often used to extrapolate past environmental conditions; carbonate clumped isotopes (Δ47) may be used to reconstruct environmental temperature, δ13C values can inform C3 or C4 vegetation, and δ18O values may provide information on precipitation and temperature. Δ47, δ13C and δ18O from pedogenic carbonates in paleosols, as well as speleothems within caves have resulted in valuable information about associated paleoenvironments. However, these techniques have not been applied consistently to the hominin evidence in this region. This study presents the first Δ47, δ13C and δ18O analysis applied to the sediment matrix in breccia deposits from two caves in the Chongzuo region of southern China, Ma Feng and Baxian. The resulting isotopic interpretations will be contextualised using faunal δ13C and δ18O values from the same caves. Furthermore, OSL dating applied to the breccia and U-series dating of an elephant tooth will provide a precise timeline for this environmental reconstruction. Problems related to the application and interpretation of breccia deposits in these complex environments will also be discussed.