FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
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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(Print or Type Responses)
1. Name and Address of Reporting Person *
Supernova Partners III LLC
  2. Issuer Name and Ticker or Trading Symbol
Supernova Partners Acquisition Co III, Ltd. [STRE]
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)
C/O SUPERNOVA PARTNERS ACQ. CO. III, LTD, 4301 50TH STREET NW SUITE 300 PMB 1044
3. Date of Earliest Transaction (Month/Day/Year)
05/06/2021
(Street)

WASHINGTON, DC 20016
4. If Amendment, Date Original Filed(Month/Day/Year)
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ 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

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 Common Stock (1) 05/06/2021   J(2)     161,638   (1)   (1) Class A Common Stock 161,638 $ 0 6,882,112 I See footnote (3)

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Supernova Partners III LLC
C/O SUPERNOVA PARTNERS ACQ. CO. III, LTD
4301 50TH STREET NW SUITE 300 PMB 1044
WASHINGTON, DC 20016
    X    

Signatures

 Supernova Partners III LLC, By: /s/ Michael S. Clifton, Manager   05/10/2021
**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) The Class B common stock will automatically convert into shares of Class A common stock at the at the time of the Issuer's initial business combination or earlier at the option of the holders thereof, on a one-for-one basis, subject to adjustment.
(2) Supernova Partners III LLC ("Sponsor") forfeited 161,638 Class B common stock to the Issuer for no consideration in connection with the underwriter's election not to exercise the remaining unused portion of the over-allotment option.
(3) Sponsor is the record holder of the warrants reported herein. Sponsor is governed by a board of managers consisting of four managers: Messrs. Rascoff, Klabin, Reid, and Clifton (the "Managers") and the approval of a majority of the Managers is required to approve any action of Sponsor. Each of the Managers disclaims beneficial ownership of the securities held of record by Sponsor.

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