Abstract A practical and efficient method for the direct trifluoromethylthiolation of unactivated C(sp 3 )H bonds by AgSCF 3 /K 2 S 2 O 8 under mild conditions is described. The reaction has a good functional‐group tolerance and good selectivity. Initial mechanistic investigations indicate that the reaction may involve a radical process in which K 2 S 2 O 8 plays key roles in both the activation of the C(sp 3 )H bond and the oxidation of AgSCF 3 .