For individuals, self-employed professionals and small companies alike, keeping track of tax obligations and filing deadlines is essential to avoid late submissions, penalties and unnecessary uncertainty. As deadlines may differ depending on the type of tax, the taxpayer’s status and the method of filing, a clear overview can be particularly useful.

For internationally active individuals and companies, it is also important to consider that additional obligations may arise in a cross-border context. This includes, for example, the Belgian non-resident income tax regime (BNI), which may apply where Belgian-source income is received without full tax residency in Belgium.

In this edition, we summarise the main tax compliance deadlines for the 2026 calendar year and briefly explain what must be reported, where filings must be made and how the relevant formalities are generally handled.

What must be reported?

All income relating to tax year 2025 must be declared, including employment income, pensions, self-employed profits or professional income, movable and immovable income, as well as tax reductions and deductible items such as pension savings, donations and childcare expenses.

For individuals subject to non-resident income tax (BNI), similar reporting obligations may arise in respect of Belgian-source income, although the applicable procedures and deadlines may differ depending on the situation.

Where must this be reported?

Via MyMinfin (Tax-on-web) or, exceptionally, by paper tax return.

How must it be reported?

Through the paper tax return received from the tax authorities, although online filing through MyMinfin (Tax-on-web) remains the preferred option of the administration.

What is it?

Voluntary advance tax payments can be made in order to avoid a tax increase.

Where and how?

Via MyMinfin, through online payment with structured reference, or by bank transfer.

What must be reported?

Periodic VAT returns including VAT due on sales and deductible VAT on purchases.

Where must this be reported?

Via Intervat, accessible through MyMinfin.

How must it be reported?

Electronically via Intervat, either manually or through file upload from accounting software.

What must be reported?

An overview of Belgian VAT clients to whom invoices exceeding EUR 250 were issued in 2025. Small businesses operating under the exemption regime must also report their total turnover, even if nil.

Where and how?

Via Intervat, by electronic filing.

What must be reported?

The filing and payment of payroll withholding tax on salaries and remuneration.

Where and how?

Mandatory electronic filing via Finprof.

When?

Monthly or quarterly, no later than the 13th or 15th day of the month following payment.

Corporate income tax

The corporate income tax return must be filed via Biztax, in principle no later than seven months after the closing date of the financial year.

For companies whose financial year coincides with the calendar year and closes on 31 December 2025, the filing deadline is normally set on 30 September 2026.

Similarly, companies that are not resident in Belgium but generate Belgian-source income may be subject to the non-resident corporate income tax regime, triggering specific filing obligations.

Annual accounts

The annual accounts must be filed with the National Bank of Belgium within 30 days following approval by the general meeting and at the latest seven months after the closing of the financial year.

What is it?

The registration and annual confirmation of the ultimate beneficial owners of companies.

Where and how?

Via the UBO register in MyMinfin.

When?

Within 30 days following incorporation or any change, and to be reconfirmed annually.