The present study investigates the potential of carbonation-cured belite-rich cement (BRC) to resist magnesium sulfate (MgSO4) and sulfuric acid (H2SO4) environments. BRC mortar was submerged in 5% and 10% MgSO4 and H2SO4 solutions. The gains of the compressive strength and mass under MgSO4 environment significantly depend upon the buffer (unreacted belite phase) left in the specimen after 28 days of curing. The lowest buffer level, found after 28 days of carbonation curing, stemmed from the higher reactivity of the belite phase as opposed to water curing followed by carbonation curing. Furthermore, degradations in the strength and mass were found in the H2SO4 environment. The presence of the calcium carbonate phase in carbonation-cured BRC mortar increased the acid resistance. An XRD analysis showed sulfate-based mineral phases in the external and core areas of a carbonation-cured BRC mortar cube, representing the higher diffusion efficiency of acid ions than magnesium ions in BRC.