Korean Tax ID (TIN) for Foreigners

Who this guide is for

• Foreigners asked for a Korean TIN by a bank or platform
• Employees completing overseas tax forms
• Foreign sole proprietors
• Non-residents receiving Korean-source income

Key points

• The correct number depends on the form and legal status.
• A foreigner registration number commonly identifies a registered foreign individual.
• A Korean business registration number identifies a registered business.
• Passport or foreign-country TIN may be fallback identifiers on some forms.
• Do not send a full identification number through insecure channels.

Step-by-step explanation

Start with the requester and form

Ask whether the requester needs a personal Korean tax identifier, a business registration number, or a foreign-country TIN. Obtain the form name and instructions instead of sending every number you have.

Match the identifier hierarchy

NTS English form instructions commonly prioritize a Korean resident or business registration number. For a foreign individual without that number, the form may use a domestic residence report number, foreigner registration number, passport number, investment registration number, or foreign-country TIN in a specified order.

Match the official name

Use the English name, order, spacing, and date of birth shown on the relevant official record. A TIN can be valid while a portal rejects it because the name or registration data does not match.

Protect the number

Treat registration and taxpayer numbers as sensitive personal data. Use official encrypted portals or secure upload tools, and mask all but the necessary digits in routine correspondence.

Documents you may need

• The form requesting the TIN
• Residence card or foreigner registration details
• Passport
• Business registration certificate
• Domestic residence report certificate
• Prior Korean tax certificate or withholding statement

Common mistakes

• Using a business number for a personal request without checking
• Entering a foreign TIN where a Korean identifier is required
• Publishing the full number in email or screenshots
• Assuming a portal error means no Korean tax record exists
• Changing name order or spelling from official records

When should you ask a tax professional?

Ask a qualified tax professional if you have income from several countries, business income, unclear tax residency, treaty questions, missing documents, late filing concerns, or a visa situation that depends on tax records. This site explains general patterns only and cannot review your personal facts.

FAQ