

Individuals ● Business ● Tax Advisory ● Payroll Services
Our Address
1441 Kapiolani Boulevard Suite 912
Honolulu, HI 96814

We file their taxes, provide bookkeeping services and
Business organization consulting.
2025 Hawaii State Tax Deadlines
Hawaii Individual Income Tax Filing deadlines and extensions for 2025 for tax professionals.
If you have clients who are residents or have been involved in significant business operations within Hawaii, then they might be required to file Hawaii State Taxes. This page covers the most important tax deadlines and tax extensions for Hawaii in 2025.
Hawaii Business Tax Deadlines for 2025
Pass-Throughs
Hawaii S Corporation & Partnership Tax Deadlines for 2025
You must file in Hawaii by April 20, 2026.
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File Online with Hawaii Tax Online
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File by Mail must be postmarked by the due date
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Form 1: N-35 – S-Corporation Income Tax Return
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Form 2: N-20 – Partnership Return of Income
Extension to File S Corporation & Partnership Taxes in Hawaii for 2025
The Extension Deadline for Hawaii pass-through entity tax returns is October 20, 2026.
Hawaii automatically grants a six-month extension on filing pass-through entity tax returns. This means you do not need to file for an extension in Hawaii.
This is an extension to FILE, not an extension to PAY – payment is still due April 20, 2026.
C Corporation
Hawaii C Corporation Tax Deadlines for 2025
Hawaii C Corporation Tax Deadlines for 2025
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File Online with Hawaii Tax Online
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File by Mail must be postmarked by the due date
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Form N-30 – Hawaii Corporation Income Tax Return
Extension to File Taxes in Hawaii for 2025
The Extension Deadline for Hawaii corporate income tax returns is October 20, 2026.
Hawaii automatically grants a six-month extension on filing corporate income tax returns. This means you do not need to file for an extension in Hawaii.
This is an extension to FILE, not an extension to PAY – payment is still due April 20, 2026.
Hawaii Individual Tax Deadlines for 2025
Estimated Tax Deadline for Hawaii 2025
Estimated tax payments are due:
April 21, 2025
June 20, 2025
September 22, 2025
January 20, 2026
See Form N-1 instructions for the amount to pay with each voucher.
Individual Tax Deadline for Hawaii 2025
You must file and pay Individual Income Taxes in Hawaii by April 20, 2026.
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File Online with Hawaii Tax Online
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File by Mail must be postmarked by the due date
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Form 1: N-11 – Residents
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Form 2: N-15 – Nonresidents or Part-Year Residents
Extension to File Taxes in Hawaii for 2025
The Extension Deadline for Hawaii individual income tax returns is October 20, 2026.
Hawaii automatically grants a six-month extension on filing personal income taxes. This means you do not need to file for an extension in Hawaii.
This is an extension to FILE, not an extension to PAY – payment is still due April 20, 2026.
Sources
HI N-35 Information
A corporation must file Form N-35 if it has elected, by filing federal Form 2553, to be treated as an S corporation for federal purposes, the IRS has accepted the election, and the election remains in effect. S corporations which are financial corporations subject to tax under chapter 241, Hawaii Revised Statutes (HRS), may not file Form N-35, but must file Form F-1, Franchise Tax Return.
Link to official form info: Hawaii N-35
Upcoming Due Dates in the Next Year:*
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* Due dates are based on the filing requirements for this form and may vary depending on your tax year.
10 Hawaii Tax Filings & Forms:
N-11 - Individual Income Tax Return
N-30 - Corporation Income Tax Return
N-20 - Partnership Return of Income
HW-14 Withholding Tax Return
UC-B6 Unemployment Quarterly Contribution Report
N-15 - Nonresident and Part-Year Resident Income Tax
N-35 - S- Corporation Income Tax Return
HW-14 - Withholding Tax Return
HW-3 Employer's Annual Return and Reconciliation of Income Tax Withheld From Wages
BUSINESS TAX FILING
We are well-versed in business tax and accounting and can work with any business including partnerships,
S-corporations, C-Corporations, LLCs, corporations, and non-profits.

Tax Filing
Income Tax Return,
Bit Coin,
Rental Properties
and..more!
Let's Save You Money this
Tax Season
Tax Services. Financial Consulting. Let Us Do the Math.
The best solution for tax advisory, strategy, and payroll.

Skilled Oahu Tax Experts

Well Rounded Tax Advice

Tailored Tax Solutions
Serving small to mid-size companies of all industries.



Diamond Head Tax Group is a Honolulu locally owned and operated business that serves individuals and small and medium business. Services include tax planning and preparation, charitable tax planning strategies, social security taxation reduction, sales tax preparation, small business strategy development, QuickBooks setup, and payroll services. Clients appreciate Diamond Head Tax Group's help, advice, flexible hours, and thoroughness.
OUR TAX SERVICES
Tax Preparation
Tax Planning
Sales Tax Preparation
Professional Payroll Services
Small Business Strategy
Roth IRA Conversion
Charitable Tax Planning
QuickBooks set up
Social Security Taxation Reduction

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Oahu Tax Services
We help individuals and businesses with tax advisory and payroll services.
Talk to one of our Oahu Tax Professionals today to start saving.

