Filed Pursuant to Rule 424(b)(3)

Registration Statement No. 333-296767

Prospectus Supplement No. 9

(To Prospectus Dated July 10, 2026)

Robo.ai Inc.

Up to 22,343,750 Class B Ordinary Shares

This prospectus supplement is being filed to update and supplement the information contained in the prospectus dated July 10, 2026, which forms a part of our registration statement on Form F-1 (Registration No. 333-296767), as amended and supplemented, with the information contained in our current report on Form 6-K furnished with the U.S. Securities and Exchange Commission on September 11, 2026. The prospectus relates to the potential offer and sale from time to time by the selling shareholder named therein or its pledgees, donees, transferees, assignees, or other successors in interest (that receive any of the securities as a gift, distribution, or other non-sale related transfer) of up to 22,343,750 Class B ordinary shares, par value US$0.002 per share, of Robo.ai Inc.

This prospectus supplement updates and supplements the information in the prospectus and is not complete without, and may not be delivered or utilized except in combination with, the prospectus, including any amendments or supplements thereto. This prospectus supplement should be read in conjunction with the prospectus and if there is any inconsistency between the information therein and this prospectus supplement, you should rely on the information in this prospectus supplement.

Our Class B ordinary shares are listed on the Nasdaq Stock Market LLC, or Nasdaq, under the ticker symbol “AIIO.” On September 10, 2026, the closing price of our Class B ordinary shares on Nasdaq was US$1.79.

We may further amend or supplement the prospectus from time to time by filing amendments or supplements as required. You should read the entire prospectus, this prospectus supplement, and any amendments or supplements carefully before you make your investment decision.

Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page 18 of the prospectus for a discussion of information that should be considered in connection with an investment in our securities.

Neither the U.S. Securities and Exchange Commission nor any other regulatory body has approved or disapproved of these securities or determined if this prospectus supplement or the prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is September 11, 2026.

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 September 2026

Commission File Number: 001-41559

Robo.ai Inc.

(Registrant’s Name)

Meydan Grandstand, 6th floor

Meydan Road

Nad Al Sheba, Dubai

United Arab Emirates

(Address of principal executive offices)

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 ☐

Termination of Chinasky Car Trading FZE Acquisition

As was previously reported, on February 19, 2026, Robo.ai Inc. (Nasdaq: AIIO) (“Robo.ai” or the “Company”), a UAE-based, U.S.-listed company, entered into a share purchase agreement (the “SPA”) through its indirectly wholly owned subsidiary, Roboai Investments L.L.C-FZ (the “Purchaser”), with Yuntao Liu (the “Seller”), the 100% equity owner of Chinasky Car Trading FZE (the “Target”), an automobile trading company incorporated in Dubai under the laws of the United Arab Emirates. Pursuant to the SPA, the Purchaser agreed to acquire from the Seller 51% of the issued and outstanding shares of the Target, for a total consideration of US$1,000,000, payable in 7,388,799 Class B ordinary shares of the Company on a pre-reverse stock split basis and with par value of US$0.0001 per share (the “Consideration Shares”).

On September 10, 2026, the Purchaser served notice of termination on the Seller pursuant to Section 11.1(b) of the SPA. Accordingly, the SPA was terminated immediately on the date of the notice. As of the date of the notice, no Consideration Shares or other securities had been issued or registered to the Seller or to any person at the Seller’s direction; no shares in the Target had been transferred to the Purchaser or to any person at its direction; and no payment of any kind had been made by either party to the other under the SPA.

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.