Personal Tax: Who Must File by March 31?

The March 31 deadline is approaching. Do you need to file personal income tax in Thailand? Here's how to determine your obligation.

 

Who MUST File

1. Thai Tax Residents

If you spent 180+ days in Thailand during 2025:

• You're a tax resident
• Must file if you had taxable income
• This applies even if you're not a Thai citizen

 

2. Anyone Who Earned Thai-Source Income

Even if you spent < 180 days, you must file if you earned:

• Salary from a Thai company
• Business income in Thailand
• Rental income from Thai property
• Interest from Thai banks (over threshold)
• Dividends from Thai companies

 

3. Employees with Withheld Tax

If your employer withheld PIT from your salary:

• You should file to claim refund (if overpaid)
• Or confirm correct amount was withheld

 

4. Business Owners Taking Income

If you own a Thai company and took:

• Salary
• Dividends
• Director fees
• Any personal income

 

Who Doesn't Need to File

Exempt Income Only

If your only income was:

• Interest < 20,000 THB/year
• Dividends already subject to withholding (and no other income)
• Gifts from family

 

Non-Residents with No Thai Income

If you:

• Spent < 180 days in Thailand
• Had no Thai-source income
• Didn't remit foreign income to Thailand

 

Income Below Threshold

If your total annual income was < 150,000 THB:

• Technically exempt from tax
• But may still want to file for record-keeping

 

Special Cases

Digital Nomads

Working remotely for foreign company while in Thailand:

If < 180 days:

• Not a tax resident
• No filing required (if no Thai income)

If 180+ days:

• Tax resident
• Should file
• Gray area: Remote work for foreign company
• Conservative approach: Declare and pay tax
• Aggressive approach: Don't declare (risky)

 

Retirees

Living in Thailand on retirement visa:

Thai income (pensions, rental):

• Must file and pay tax

Foreign pensions not remitted:

• Not taxable in Thailand
• No filing required

Foreign pensions remitted to Thailand:

• May be taxable (depends on treaty)
• Should consult tax advisor

 

Spouses of Thai Nationals

Same rules apply:

• 180-day test determines residency
• Thai-source income is taxable
• Can file jointly or separately

 

Income Thresholds

Tax-Free Allowances

• Personal allowance: 60,000 THB
• Spouse allowance: 60,000 THB (if filing jointly)
• Child allowance: 30,000 THB per child

Example:

• Single person
• Income: 150,000 THB
• Less personal allowance: 60,000 THB
• Taxable income: 90,000 THB
• Tax owed: 1,500 THB (5% on first 150K above allowance)

 

Determining Your Status

Step 1: Count Your Days

Did you spend 180+ days in Thailand in 2025?

• Yes: Tax resident → Must file if you had income
• No: Non-resident → File only if Thai-source income

 

Step 2: Calculate Your Income

Total all income from:

• Salary
• Business profits
• Rental income
• Investment income
• Other sources

 

Step 3: Check Exemptions

Subtract:

• Personal allowance (60,000 THB)
• Other allowances (spouse, children)

If result > 0: You likely need to file

 

Penalties for Not Filing

Late Filing

• Penalty: 1,000-2,000 THB
• Plus: 1.5% per month on unpaid tax

 

Intentional Evasion

• Fine: Up to 200% of tax owed
• Criminal charges: Possible imprisonment

 

When in Doubt, File

Benefits of filing even if not required:

• Creates tax record
• May get refund if tax was over-withheld
• Demonstrates compliance
• Useful for visa extensions, loans, etc.

Cost: Minimal (can file yourself or pay accountant 3,000-5,000 THB)

 

Next Steps

If you determine you must file:

1. Gather documents (salary statements, receipts)
2. Calculate deductions (we'll cover this tomorrow)
3. Prepare Form Por Ngor Dor 90/91
4. File by March 31 (or May 31 if e-filing)

 

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Related Service: Accounting & Tax Compliance — Personal tax filing assistance for foreign residents.