Company: SUZ
Filing Date: 2025-09-02
Form Type: 6-K
Source: 0000909327-25-000035
Chunk: 0

Company: Suzano S.A.
Filing Date: 2025-09-02
Form: 6-K
Chunk 0
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<div align='center'>UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, DC 20549</div>

#### FORM 6-K
<div align='center'>REPORT OF FOREIGN PRIVATE ISSUER
PURSUANT TO RULE 13a-16 OR 15d-16
UNDER THE SECURITIES EXCHANGE ACT OF 1934</div>

#### For the month of September, 2025.

#### Commission File Number 001-38755

#### Suzano S.A.
<div align='center'>(Exact name of registrant as specified in its charter)</div>

#### SUZANO INC.
<div align='center'>(Translation of Registrant’s Name into English)

Av. Professor Magalhaes Neto, 1,752
10th Floor, Rooms 1010 and 1011
Salvador, Brazil 41 810-012 (Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F. Form 20-F ☑ Form 40-F ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ☐</div>

Enclosures:

Exhibit 99.1 – Minutes of the Board of Directors' Meeting

### SIGNATURE
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

#### Date: September 2

#### nd

#### , 2025
|        |     | SUZANO S.A.                                      |
| By:    |     | /s/ Marcos Moreno Chagas Assumpção               |
| Name:  |     | Marcos Moreno Chagas Assumpção                   |
| Title: |     | Vice-President of Finance and Investor Relations |