The last day to file a U.S. individual tax return for the 2024 tax year is April 15, 2025. If more time is needed, taxpayers can file Form 4868 to request an extension to file by October 15, 2025, but any taxes owed must still be paid by April 15, 2025 to avoid interest and penalties.

For U.S. expats, there is an automatic extension to June 15, 2026, for the 2025 tax year, and further extensions can extend the filing deadline to October 15, 2026, if Form 4868 is filed in time.

In the UK, for comparison, the deadline for the 2024/25 tax year self- assessment online filing is January 31, 2026, with penalties for late filing after this date.

For filings in the Netherlands, the standard deadline for the 2024 tax year is May 1, 2025, with possible extensions until September 1, 2025.

So, specifically for U.S. individual taxpayers the last day to file without extension for the 2024 tax year is April 15, 2025. With extensions, the latest is October 15, 2025.