Timor-Leste tax filing deadlines 2026: the complete calendar

Timor-Leste's tax calendar is, mercifully, short. There are essentially two cadences — monthly and annual — and most of the year you only need to remember one date: the 15th.

Monthly tax filings cover Sales Tax, Service Tax, Wage Income Tax (WIT), Withholding Tax (WHT), and any applicable excise on imports. They are filed and paid by the 15th of the following month. So January's monthly taxes are due 15 February; February's are due 15 March; and so on.

Annual filings are concentrated in the first quarter of the following year. The Corporate Income Tax return is due by the last day of the third month after year-end — for a calendar-year company, that means 31 March. The Annual Employer Wage Income Tax Withholding Form is due on the same date.

Beyond that, larger businesses pay CIT in quarterly instalments, and a handful of import-specific filings can fall outside the monthly cadence. We cover those below.

January 2026 — By the 15th: file and pay monthly taxes for December 2025 (Sales, Service, WIT, WHT, excise). This is the first filing of the new tax year, and it covers the last month of the previous calendar year — easy to get confused about which year you are reporting on.

February 2026 — By the 15th: monthly taxes for January 2026.

March 2026 — Two dates matter this month. By the 15th: monthly taxes for February 2026. By 31 March: the annual Corporate Income Tax return for the 2025 tax year (for calendar-year companies) and the Annual Employer Wage Income Tax Withholding Form for 2025. This is the heaviest filing month of the year.

April 2026 — By the 15th: monthly taxes for March. If your business pays CIT in quarterly instalments, this is also when the Q1 instalment falls due in most year-end configurations.

May 2026 — By the 15th: monthly taxes for April. A quieter month.

June 2026 — By the 15th: monthly taxes for May. Mid-year — a good time to reconcile the year to date against the first-half budget and catch any drift before September.

July 2026 — By the 15th: monthly taxes for June. Q2 CIT instalment if applicable.

August 2026 — By the 15th: monthly taxes for July.

September 2026 — By the 15th: monthly taxes for August.

October 2026 — By the 15th: monthly taxes for September. Q3 CIT instalment if applicable.

November 2026 — By the 15th: monthly taxes for October.

December 2026 — By the 15th: monthly taxes for November. Also: this is the month to close books cleanly for the calendar year-end. Year-end stocktake, accruals, and supporting documentation should all be tidied so January and February do not become a scramble. Q4 CIT instalment may fall due depending on instalment configuration.

Each 15th, the same set of returns and payments goes in. Most businesses won't file every category every month — but here is the list, in case any apply.

Sales Tax — if you imported taxable goods in the previous month. The rate is 2.5% of customs value, paid at the time of import; the monthly return reconciles it.

Service Tax — if you provided hotel, restaurant, bar, or telecom services with gross consideration over USD 500 in the previous month. The rate is 5%.

Wage Income Tax — if you paid wages in the previous month. The rate is 10% on the portion above USD 500 per month for residents, and 10% flat for non-residents.

Withholding Tax — if you made payments in the previous month on which WHT should have been deducted: non-residents, royalty payments, professional services, construction services, and certain rents.

Selective Consumption Tax (excise) — if you imported excisable goods in the previous month, including tobacco, alcohol, fuel, and some vehicles.

The actual return goes on a Monthly Taxes Form, filed in three copies, with payment to Banco Nacional Ultramarino (BNU) or via the P24 electronic payment system.

If your business has corporate income tax exposure above a threshold set under Law 8/2008, ATTL requires CIT to be paid in quarterly instalments rather than as one annual lump.

Instalment due dates align with the end of each fiscal quarter. For a calendar-year company, that means roughly: Q1 due in early April, Q2 due in early July, Q3 due in early October, Q4 due in mid-December — with the final reconciliation in the 31 March annual return that follows.

For smaller businesses below the instalment threshold, no quarterly payments are required; the full CIT settles in the annual return.

For monthly taxes: the Monthly Taxes Form, filed in three copies — one copy stays with you, one with the bank, one with ATTL.

For annual CIT: the Annual Income Tax Form, with the schedule that matches your status — natural person operating a business, legal entity, or non-resident.

For the annual employer obligation: the Annual Employer Wage Income Tax Withholding Form — a summary of all WIT withheld and remitted in the year, due 31 March.

For Social Security: a separate INSS form, filed monthly, through INSS rather than ATTL. Different office, different deadline channel.

ATTL maintains the current versions of every form on its Documents & Forms portal. Print three copies. Sign the original. The bank stamps your stamped copy as proof of payment.

For most filings, payment moves through Banco Nacional Ultramarino (BNU). You file the Monthly Taxes Form in three copies and deliver one with payment at a BNU branch; the bank stamps your remaining copies as proof.

ATTL also operates an electronic payment system known as P24. The mechanics differ by tax type, but the upshot is that you can settle the payment without a physical visit to BNU. For businesses that file every month, the time saved is real, and the audit trail is cleaner.

Social Security contributions are a separate channel through INSS — they cannot be combined into one BNU deposit slip with the ATTL filings. Plan for two payments each month, not one.

If a 15th-of-the-month deadline falls on a Saturday, Sunday, or a Timor-Leste public holiday, it moves to the next business day. Same rule for the 31 March annual return.

Worth knowing: Timor-Leste's public-holiday calendar includes a number of religious and national observances that shift year to year. Check the official calendar at the start of each tax year and mark the relevant dates in advance — Easter, Restoration of Independence Day, All Saints' Day, and the year-end period all have a way of catching out an automated reminder system set to the 15th.

A missed monthly filing triggers a late-filing penalty almost immediately. The penalty framework sits in Law 8/2008 (the Tax and Duties Act): a percentage fine on the tax owed, plus monthly interest on the unpaid balance until the position is settled. Wilful evasion is treated more severely than simple late filing.

The practical reality for most businesses is that small misses compound. Three months of missed monthly returns become a six-month catch-up exercise that the business absorbs in legal fees and accountant time. The penalties are recoverable; the time isn’t.

The fix isn't memorising the penalty schedule. It's having a calendar discipline so the 15th never sneaks up. That's what the rest of this guide is for.

This is the operational rhythm we run every month for clients across Dili — preparing the Monthly Taxes Form, reconciling against bank statements, filing through BNU or P24, and handling the 31 March annual returns when the new year arrives.

If the 15th has become a stressful date in your business, book a free 30-minute consultation. We'll look at how filing is currently handled, what's slipping, and what it would take to get the calendar under control.