Company: TEN-PE
Filing Date: 2025-06-25
Form Type: 6-K
Source: 0001193125-25-146128
Chunk: 0

Company: TSAKOS ENERGY NAVIGATION LTD
Filing Date: 2025-06-25
Form: 6-K
Chunk 0
---
### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of June 2025

Commission File Number 001-31236

### TSAKOS ENERGY NAVIGATION LIMITED
(Translation of registrant’s name into English)

367 Syngrou Avenue, 175 64 P.

Faliro, Athens, Greece

(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 ☐

EXHIBIT INDEX

SIGNATURES 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: June 25, 2025

| TSAKOS ENERGY NAVIGATION LIMITED |     |                                       |
| By:                              |     | /s/ George Saroglou                   |
|                                  |     | George Saroglou                       |
|                                  |     | President and Chief Operating Officer |