The management of synchronous asymptomatic colonic metastases from primary esophageal squamous cell carcinoma (ESCC) has not yet been reported. A 64-year-old male patient was diagnosed with middle thoracic ESCC. The patient received chemoradiotherapy and incomplete response/stable disease was achieved. Preoperative colonoscopy revealed a 1.0-cm submucosal tumor at the splenic flexure of the colon, and biopsy results indicated possible metastasis from primary ESCC. The patient underwent subtotal esophagectomy and the colonic tumor was excised. A postoperative pathological diagnosis confirmed that the colonic tumor had metastasized from primary ESCC. Even though the patient was discharged 18 days after surgery without any complications, he died on the 72nd postoperative day due to multiple bone metastases and pleural dissemination. Our findings suggest that even with well-controlled and asymptomatic colonic metastasis from primary esophageal lesions, the prognosis of patients with primary ESCC is poor.