Neutrophils (Neuts) form the first line of defence, responding rapidly via ROS production, phagocytosis, degranulation, NETosis, and intercellular communication. These Ca²⁺-dependent functions rely on store-operated Ca²⁺ entry (SOCE), where STIM proteins activate Orai channels following ER Ca²⁺ depletion. Using a C/EBPα-driven STIM1/2 knockout (Stim1/2dKO) in myeloid cells, we observed loss of SOCE and ROS production, validating our model. Combining this with a Ca2+ probe (Salsa6f), we found reduced spontaneous PLC-dependent Ca²⁺ flickering in Stim1/2dKO mouse Neuts. This was accompanied by a spreading defect, observed in both Stim1/2dKO and PLC-inhibited Neuts. Interestingly, STIM-Orai interactions at ER-PM membrane contact sites (MCS) persisted, with increased “STIM-less” MCS, likely mediated by junctate or ESyt2. These MCS appeared more rigid and less dynamic, reducing Ca²⁺ activity, actin polymerisation, and IP₃R proximity to the PM. Our findings suggest dynamic STIM-containing MCS are crucial for IP₃R positioning and PLC-dependent Ca²⁺ signalling, which drive Neut spreading through actin polymerisation.