Lymphatic spread of colon cancer usually occurs via mesenteric vessels (superior and inferior mesenteric vessels), but inguinal lymph node (LN) metastasis from colon cancer is extremely rare with only few reported cases in the literature. A case of a 35-year-old female patient with a history of sigmoid cancer underwent sigmoidectomy and left salpingo-oopherectomy in 2016 and received adjuvant chemotherapy then presented in 2023 with metastatic left inguinal LNs and underwent left inguinal LN dissection. We reported a rare case of isolated metachronous inguinal lymph node metastasis from colon cancer with a round ligament route of spread as the hypothesized mechanism. Surgical resection with inguinal LN dissection is the preferred treatment option for isolated inguinal lymph node metastasis from colon cancer followed by adjuvant chemotherapy, yet long term follow-up data is needed to support this strategy.