We explore the breaking effects of the SU (3) flavor symmetry in the singly Cabibbo-suppressed anti-triplet charmed baryon decays of B c → B n M , with B c = ( Ξ c 0 , Ξ c + , Λ c + ) and B n ( M ) the baryon (pseudo-scalar) octets. We find that these breaking effects can be used to account for the experimental data on the decay branching ratios of B ( Λ c + → Σ 0 K + , Λ 0 K + ) and R K / π ′ = B ( Ξ c 0 → Ξ - K + ) / B ( Ξ c 0 → Ξ - π + ) . In addition, we obtain that B ( Ξ c 0 → Ξ - K + , Σ - π + ) = ( 4.6 ± 1.7 , 12.8 ± 3.1 ) × 10 - 4 , B ( Ξ c 0 → p K - , Σ + π - ) = ( 3.0 ± 1.0 , 5.2 ± 1.6 ) × 10 - 4 and B ( Ξ c + → Σ 0 ( + ) π + ( 0 ) ) = ( 10.3 ± 1.7 ) × 10 - 4 , which all receive significant contributions from the breaking effects, and can be tested by the BESIII and LHCb experiments.