Washington S Corporation Tax Deadlines 2026

Complete guide to S Corporation filing dates, extensions, estimated payment schedules, and required forms in Washington for the 2026 tax year. Washington does not have a state income tax, so S Corporation entities only need to file federal returns.

Washington S Corporation filing deadline

No state individual income tax. Other business taxes may apply.

N/A

Due: N/A

Form: N/A

Estimated payments

No state estimated payment schedule listed.

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Due: N/A

Washington S Corporation Tax Calendar at a Glance

EventDate

FAQ

When is the S Corporation tax filing deadline in Washington for 2026?

Washington does not have a separate state filing requirement for S Corporation entities. Check with Washington Department of Revenue for the latest information.

Does Washington require S Corporation estimated tax payments?

Estimated payments are not typically required at the entity level for S Corporation in Washington, but confirm with Washington Department of Revenue.

What form do I file for a S Corporation in Washington?

S Corporation entities in Washington file using Form N/A. You can download the form from Washington Department of Revenue at https://dor.wa.gov.

Can I get an extension for my Washington S Corporation tax return?

Check with Washington Department of Revenue for extension options for S Corporation entities in Washington.

What are the penalties for filing late in Washington?

Washington typically charges a failure-to-file penalty (usually 5% of unpaid tax per month, up to 25%) and a failure-to-pay penalty (usually 0.5-1% per month). Interest also accrues on unpaid balances. Filing for an extension by the original deadline avoids the failure-to-file penalty but not the failure-to-pay penalty.

Where can I file Washington S Corporation taxes?

File through Washington Department of Revenue. Visit https://dor.wa.gov for e-filing options, downloadable forms, and payment portals.

Other Entity Types in Washington

S Corporation Deadlines in Neighboring States