Currently available drugs to treat malaria are often ineffective due to the acquisition of drug resistance. In this context, drugs with innovative modes of action and no liability to cross-resistance are urgently needed. Recently, subtilisin-like protease 1, a P. falciparum serine protease involved in merozoite egress from red blood cells and invasion, has been identified as potential drug target. We describe herein the development of a series of potent PfSUB1 inhibitors. Combining a straightforward synthetic approach, an in depth structure–activity study and in silico investigation, we identified the most potent inhibitors known to date, characterized by an improved enzyme inhibitory potency and a reduced peptidic character over the prototypic peptides.