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, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * MOSLEY WILLIAM D   2. Issuer Name and Ticker or Trading Symbol Seagate Technology plc [STX] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) EVP, Sales and Marketing (Last) (First) (Middle) SEAGATE TECHNOLOGY PLC, 10200 S. DE ANZA BOULEVARD 3. Date of Earliest Transaction (Month/Day/Year) 11/04/2011 (Street) CUPERTINO, CA 95014 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 Ordinary Shares 11/04/2011   M   100,000 A $ 4.045 122,290.5977 (1) (2) D   Ordinary Shares 11/04/2011   S   100,000 D $ 18 (3) 22,290.5977 D   Ordinary Shares 11/07/2011   M   19,814 A $ 13.73 42,104.5977 D   Ordinary Shares 11/07/2011   S   19,814 D $ 18.5 (4) 22,290.5977 D   Ordinary Shares 11/07/2011   M   1,019 A $ 13.73 23,309.5977 D   Ordinary Shares 11/07/2011   M   10,000 A $ 4.045 33,309.5977 D   Ordinary Shares 11/07/2011   S   11,019 D $ 18.5 (4) 22,290.5977 D

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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

NQ Stock Option

$ 4.045

11/04/2011

M

100,000

01/30/2010(5)

01/30/2016

Ordinary Shares

100,000

$ 0

550,000

D

NQ Stock Option

$ 13.73

11/04/2011

M

19,814

09/12/2009(6)

09/12/2015

Ordinary Shares

19,814

$ 0

30,186

D

NQ Stock Option

$ 13.73

11/07/2011

M

1,019

09/12/2009(6)

09/12/2015

Ordinary Shares

1,019

$ 0

29,167

D

NQ Stock Option

$ 4.045

11/07/2011

M

10,000

01/30/2010(5)

01/30/2016

Ordinary Shares

10,000

$ 0

540,000

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
MOSLEY WILLIAM D SEAGATE TECHNOLOGY PLC 10200 S. DE ANZA BOULEVARD CUPERTINO, CA 95014			EVP, Sales and Marketing

Signatures

/S/ Roberta S Cohen for William D Mosley		11/08/2011
**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)	Includes 686 shares purchased under the employee stock purchase plan on July 29, 2011.
(2)	On July 8, 2011, the Compensation Committee of the Board of Directors of the Issuer authorized and confirmed that the performance metrics were met with respect to 5,500 of the 22,000 Performance Shares granted to Mr. Mosley on September 13, 2010 and reported on Mr. Mosley's Form 4 dated September 15, 2010.
(3)	The Sale reported on this Form 4 was affected by a 10b5-1 trading plan adopted by the Reporting Person on May 24, 2011.
(4)	The Sale reported on this Form 4 was affected by a 10b5-1 trading plan adopted by the Reporting Person on February 22, 2011.
(5)	Options granted to the Reporting Person under the 2004 Stock Compensation Plan are subject to a four-year vesting schedule. One quarter of the shares vested on January 30, 2010. The remaining shares vest proportionally each month over the 36 months following January 30, 2010.
(6)	Options granted to the Reporting Person under the 2004 Stock Compensation Plan and are subject to a four-year vesting schedule. One quarter of the shares vested as of September 12, 2009. The remainder of the shares vested proportionally each month over the 36 months following September 12, 2009.

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