Granular cell tumours (GCTs) are rare soft tissue tumours originating from Schwann cells. Due to potential malignant transformation, complete endoscopic resection should be aimed for. We report on a 49-year-old patient with two synchronous GCTs found in the caecum and the ascending colon, respectively. Synchronous endoscopic full-thickness resection (EFTR) using an all-in-one full-thickness resection device (FTRD) was performed under propofol sedation. Completeness of resection was proven histologically. No adverse events occurred. We report safe and complete simultaneous EFTR of two synchronous colonic GCTs.