In this work, we have investigated how model lipid membranes are permeabilized to monoatomic ions by several natural antimicrobial peptides (AMPs). Despite a large body of work demonstrating AMP induced permeabilization in both in vitro studies and on model membranes, there has been a long-standing debate on the specific molecular mechanisms behind this observed permeabilization. Perhaps the most commonly presented hypothesis has been that of stable structural pores. In this case, several AMPs are proposed to insert across the membarne, i.e. in a transmembrane fashion, and either assemble to form a "barrel stave" pore or cooperatively induce a "toroidal" pore of very high lipid curvature. While these well-defined transmembrane structures might be appealing from a mechanical point of view, they are entropically unfavorable. As pointed out by Wimley , there has been very little direct experimental evidence to support them. Instead the "interfacial activity model" was proposed as an alternative, where the permeabilization is attributed to a disruption of the local lipid packing upon peptide insertion into the lipid head-tail interface in the outer membrane leaflet. It has proven difficult to provide concrete experimental evidence for either, as permeability and structural characterization studies have typically relied on very different methodologies, making it highly challenging to relate the two.