Ion channels play pivotal roles in many of the body’s physiological processes such as the regulation of the heart beat, release of insulin, and the initiation and modulation of all nerve impulses. They perform these functions through a combination of ion selection and tight regulation of the ion movement across the membrane which is known as gating. For inwardly rectifying K⁺ (Kir) channels the KirBac1.1 crystal structure revealed the closed state in which ion movement is blocked through a hydrophobic gate. Presentation of two new crystal structures of the related KirBac3.1 channel that were captured in intermediate gating states between the closed and open conformations illustrates the conformational changes that occur during gating. These structures uncover how for this family of K⁺ channels gating involves a coordinated change in salt bridge connections between the cytoplasmic domains, reveals the location of a spermine binding site which is important in the rectification process and shows an unforeseen flexibility between the transmembrane sections and the cytoplasmic domains.