Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * CGC III Sponsor LLC 2. Issuer Name and Ticker or Trading Symbol Cartesian Growth Corp III [CGCT] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 505 FIFTH AVENUE, 15TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 03/31/2026 (Street) NEW YORK, NY 10017 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A ordinary shares 03/31/2026 P 300,000 A $10.277 300,000 D(1) Class A ordinary shares 04/01/2026 P V 671,000 A $10.299 971,000 D(1)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Class B ordinary shares

(2)

(2)

(2)

Class A ordinary shares

6,800,000

6,800,000

D(3)

Class B ordinary shares

(2)

(2)

(2)

Class A ordinary shares

100,000

100,000

I

See footnote(3)

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
CGC III Sponsor LLC 505 FIFTH AVENUE, 15TH FLOOR NEW YORK, NY 10017		X
Yu Peter 505 FIFTH AVENUE, 15TH FLOOR NEW YORK, NY 10017	X	X	Chairman and CEO

Signatures

/s/ Thomas Martin, Attorney-in-Fact		04/02/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Represents Class A ordinary shares of Cartesian Growth Corporation III (the "Issuer") held directly by Pangaea Three-B, LP ("Pangaea"). Pangaea is controlled by Peter Yu. Consequently, Mr. Yu may be deemed to share voting and dispositive control over the securities held by Pangaea, and thus to share beneficial ownership of such securities. Each of Pangaea and Mr. Yu disclaims beneficial ownership of such securities except to the extent of its or his pecuniary interest therein.
(2)	The Class B ordinary shares of the Issuer have no expiration date and will automatically convert into Class A ordinary shares concurrently with or immediately following the consummation of the Issuer's initial business combination, or earlier at the option of the holder, on a one-for-one basis, subject to adjustment, as described in the Registration Statement on Form S-1 (File No. 333-284565) (the "Registration Statement") related to the Issuer's initial public offering (the "IPO").
(3)	Represents 6,800,000 Class B ordinary shares held directly by the Sponsor and 100,000 Class B ordinary shares held directly by CGC III Sponsor DirectorCo LLC ("DirectorCo") (of which 90,000 shares are held by DirectorCo for the benefit of the Issuer's independent directors). The Sponsor is the sole managing member of DirectorCo. Pangaea is the sole member of the Sponsor and is controlled by Peter Yu. Consequently, each of Pangaea and Mr. Yu may be deemed to share voting and dispositive control over the securities held by the Sponsor and DirectorCo, and thus to share beneficial ownership of such securities. Each of Pangaea and Mr. Yu disclaims beneficial ownership of such securities except to the extent of its or his pecuniary interest therein.

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