INTRODUCTION: Gastric cancer was the fifth leading cause of cancer-related mortality worldwide in 2022. Peritoneal recurrence, after curative gastrectomy and systemic chemotherapy occurs in 40–60% of patients and significantly reduces survival. This pilot study evaluated the safety and feasibility of adding pressurised intraperitoneal aerosol chemotherapy with oxaliplatin (PIPAC-O+) to standard perioperative chemotherapy in patients with resectable gastric cancer at high risk of recurrence. METHODOLOGY: This prospective, single-centre, non-randomised, open-label pilot trial included patients with gastric adenocarcinoma treated with curative intent. High-risk features included: poorly cohesive subtype with signet cells, serosal involvement on laparoscopy, positive peritoneal cytology, high nodal burden on imaging, age <50 years, or proximal tumour location. As per protocol, PIPAC-O+ (92 mg/m²) was administered 4 weeks after neoadjuvant FLOT chemotherapy, followed by gastrectomy with lymphadenectomy 2 weeks later. The primary outcome was safety and feasibility, assessed via perioperative morbidity and treatment interruptions. Secondary outcomes included length of stay, cytology conversion, perioperative morbidity, progression-free survival, overall survival, and peri-interventional quality of life. RESULTS: Ten patients (median age 55, range 44–82) were enrolled between 2021–2025. All received neoadjuvant FLOT, and 90% completed adjuvant FLOT. PIPAC-O+ did not delay or interrupt standard treatment. Median post-procedure stay was 1 day. No PIPAC-O+–related morbidity or mortality occurred. One patient experienced transient bloating, fatigue, and cold sensitivity; another had nausea. No other CTCAE-grade events were reported. Quality of life was maintained. CONCLUSION: PIPAC-O+ is a safe and feasible adjunct to standard perioperative therapy in high-risk resectable gastric cancer.