How do I get a tax refund when I permanently leave Korea?

If you were an employee, ask your company's HR for an early year-end tax settlement (연말정산) before your last day, since you may be owed an income tax refund, or you can file later through Hometax. Separately, claim your National Pension lump-sum refund if you qualify (your country has a lump-sum agreement or reciprocity with Korea, or you were on E-9 or H-2 status), applying at an NPS office within a month before departure with your passport, ARC, flight ticket and bank details; on a weekday departure from Incheon you can then collect it at the NPS airport counter. Keep your Korean bank account open until the refunds actually arrive.