Tapia syndrome is characterized by unilateral tongue paralysis, hoarseness, and dysphagia. It is often associated with issues in the lower cranial nerves and is rarely caused by malignant tumors.A 71-year-old Japanese male with prostate cancer and bone metastases experienced severe headaches, oral discomfort, dysphagia, and hoarseness for a month. Neurological examination revealed left-sided tongue atrophy and left vocal cord paralysis, suggesting problems with cranial nerves IX and XII. CT scans showed bone metastasis in the left occipital bone. Brain MRI showed no brain or meningeal metastasis, but neck MRI revealed a mass near the left hypoglossal canal. His prostate-specific antigen (PSA) level was 53.2 ng/mL. Based on these findings, we diagnosed him with occipital bone metastasis of prostate cancer with Tapia syndrome. We treated him with palliative radiation therapy (RT), delivering 30 Gy in 10 fractions over two weeks. We did not use drug treatment or chemotherapy due to side effects and the patient's preferences. After just one day of RT, his severe headache and oral discomfort significantly improved. By the end of the two-week treatment, his hoarseness had also improved, and he was able to eat. However, tongue atrophy had not improved three months after RT.We presented a unique case of palliative RT for occipital bone metastasis of prostate cancer with Tapia syndrome. Within two weeks, the patient's headache and dysphagia had greatly improved, although tongue atrophy remained partially unresolved after palliative RT.