Tax season 2026: Get ready to file

The new tax year is approaching, and that means it’s time to start preparing for your 2025 income tax return. For internationals living in the Netherlands, the Dutch system can feel overwhelming, but with timely preparation and a clear understanding of the 2026 rules, you can avoid hiccups. 

Key dates to mark in your calendar for the 2026 tax season

First and most importantly, here are the key dates you need to bear in mind for the 2026 tax season in the Netherlands:

• March 1, 2026: The Dutch Tax Office typically opens the income tax submissions for the 2025 tax year. 
• April 1, 2026: If you file before this date, the Belastingdienst generally aims to issue an assessment before July 1, 2026.
• May 1, 2026: Standard deadline for submitting your income tax return.

Important changes to keep in mind

Unlike in previous years, there actually aren’t that many tax adjustments coming in 2026, but one change will particularly affect many expats, especially those who qualify for the 30% ruling. 

Below are the key updates with clarified timelines:

1. End of partial foreign tax liability for most 30% ruling holders

As of January 1, 2026, employees with a valid 30% ruling can no longer opt for the partial foreign tax liability in their Dutch income tax filing.

Specifically, this means you will no longer be exempt from declaring and paying tax on Box 2 and Box 3 income (savings, investments, worldwide assets).

One major exception

However, this change might not happen for you immediately, as there is a transition period in place. If you already benefited from the 30% ruling in December 2023, you may continue to opt for partial foreign tax liability for tax years 2025 and 2026.

This exemption ends fully as of the 2027 income tax return.

Am I exempt?

If your five-year 30% ruling period began on or after 1 January 2024, you will not fall under the transitional rule.

You must therefore declare all worldwide Box 3 assets starting with your 2025 tax return (that you will submit in 2026).

This marks the accelerated phase-out of the expat-friendly “partial non-resident taxpayer” scheme following recent parliamentary decisions.

Filing your Box 3 return for the first time in 2026? Blue Umbrella can help! 

2. Tax-free allowance in Box 3

For the 2025 income tax return, the tax-free allowance for savings and investments has increased slightly compared to 2024.

The tax-free allowance remains at:

• €57.684 per person
• €115.728 for fiscal partners filing jointly 

For reference, in 2024, the allowance was €57.000 per person and €114.000 for fiscal partners.

3. Assumed return on shares

The notional return rate used to tax share portfolios in Box 3 has not increased for the 2025 income tax year and remains at 5,88%.

By comparison, the assumed return on shares in 2024 was slightly higher than in 2023, at 6,04%.

Taxpayers may still challenge the fictional return by demonstrating their actual investment results, although this requires detailed calculations and supporting documentation. In this case, it’s worth consulting with a tax advisor. 

4. Option to file based on actual returns

Taxpayers may still request Box 3 to be assessed on their actual investment results instead of the fictional rate.

According to tax advisory firms such as Blue Umbrella, this must be done by first filing the standard return and then submitting a formal objection, a process that can be complicated.

5. Lower property transfer tax for investors

Starting in 2026, the transfer tax (stamp duty) for property purchased as an investment will decrease from 10,4% to 8%.

What these changes mean for you

For many expats, especially those who benefit from the 30% ruling, the largest impact is the expanded obligation to declare worldwide savings, investments, and certain real estate in Box 3.

Whether foreign property is taxed depends on the specific tax treaty between the Netherlands and the country where the property is located.

Because 2026 is also a year in which the government continues to correct unlawful Box 3 assessments (following court rulings), administration may be more complex than usual.

Tips for a smooth 2026 tax season

Here are our top tips for a smooth and stress-free 2026 tax season:

Start collecting documents early

If you will be declaring Box 3 assets for the first time, begin gathering documents, especially records that show actual returns, in case you wish to dispute the standard fictional return.

Understand your new obligations

Know when you need to file. Remember that:

• If your 30% ruling started after January 1, 2024, you must declare worldwide Box 3 assets for the 2025 tax year onward.
• If you already had the 30% ruling in December 2023, you may still opt for partial foreign tax liability for 2025 and 2026, but not from 2027 onward.

Consider professional help for Box 3 appeals

Filing based on actual returns requires calculations and supporting documentation. This is no easy feat to accomplish on your own, so it’s worth working with a tax advisory service that offers a specialised service for first-time Box 3 filers, such as Blue Umbrella.

Make it a stress-free filing season

The Belastingdienst will be expecting your 2025 tax return by mid-2026, so it’s wise to prepare ahead of time. Staying informed and organised will help ensure a smooth filing process. Good luck!