Foreign bodies in the urinary tract are rare in paediatric patients, more often affecting adolescent boys. Symptoms are non-specific and include recurrent urinary tract infections, abdominal pain, dysuria, haematuria, and frequent urination. Medical history, physical examination, and imaging are key to diagnosis. The article presents three cases of self-insertion of metallic foreign bodies into the urinary bladder by adolescents. First two cases are teenage boys with recurrent urinary tract infections. Magnetic balls were found in their bladders, though self-insertion was not disclosed during history taking. The third case is a teenage girl who was admitted to the hospital due to self-insertion of a foreign body into the bladder. A foreign body should always be considered in the differential diagnosis of patients with prolonged and unresponsive urinary symptoms. Early recognition and thorough history taking are essential for effective management.