Portal vein thrombosis (PVT) is most commonly seen in people with predisposing conditions such as cirrhosis, hepatobiliary malignancies, infectious or inflammatory abdominal disease, or haematologic disorders. However, the incidence of idiopathic portal vein thrombosis in non-cirrhotic people is low and approximately 25% of existing cases have no identifiable cause. If untreated, complications can include portal hypertension, a cavernous transformation of the portal vein, varices, septic thrombosis, or intestinal ischemia. We report the case of a 27-year-old female who presented to her general practitioner with two weeks of epigastric pain. She was referred for an upper abdominal USG and CT imaging, which identified portal vein thrombosis with a normal appearance of the gallbladder, liver, and spleen. Thrombophilia screen was negative for Factor V Leiden and prothrombin mutations and lupus anticoagulant. The tumour markers alpha-fetoprotein and carcinoembryonic antigen were also within normal limits. The patient was started on rivaroxaban indefinitely following advice from a vascular surgeon and haematologist. Subsequent follow-up imaging also revealed cavernous transformation of the portal vein. We present this case to discuss the diagnosis, management and treatment of this patient and to review the current evidence available in managing idiopathic portal vein thrombosis in non-cirrhotic patients, especially the role of anticoagulation in chronic cases.