Ownership Submission
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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(Print or Type Responses)
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, 920 DISC DRIVE		 3. Date of Earliest Transaction (Month/Day/Year)
09/13/2010
(Street)

SCOTTS VALLEY, CA 96066		 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
Performance Stock Shares 09/13/2010   A   22,000 (1) A $ 0 39,922.5977 D  
Performance Stock Units 09/13/2010   A   61,120 (2) A $ 0 101,042.5977 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 Options $ 11.065 09/13/2010   A   137,500   09/13/2011(3) 09/13/2017 Common Shares 137,500 $ 0 137,500 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
MOSLEY WILLIAM D
SEAGATE TECHNOLOGY
920 DISC DRIVE
SCOTTS VALLEY, CA 96066		       EVP, Sales and Marketing  

Signatures

 /S/ Roberta S Cohen for William D Mosley   09/15/2010
**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) Consists of a grant of restricted stock shares awarded to the Reporting Person under the 2004 Stock Compensation Plan for no consideration. Each restricted stock share represents a contingent right to receive one share of Seagate common stock. Subject to the Reporting Person's Continuous Service with the Coompany, vested shares to be released to the reporting person on each of the first four anniversaries of the vesting commencement date of September 13, 2010.
(2) Consists of a grant of performance stock units awarded to the Reporting Person under the 2004 Stock Compensation Plan for no consideration. Each performance stock unit represents a contingent right to receive one share of Seagate common stock. The vesting for these awards issued under the 2004 Stock Compensation Plan is subject to both continuous employment and specified performance goals.The Award Agreement provides that performance units will vest after the end of a performance period, currently contemplated to be three years, subject to both the continued employment of the participant by the Company and the achievement of certain performance objectives established by the Board of Directors and set forth in the Award Agreement. The Board of Directors presently intends that the performance goals will be a three-year average return on invested capital goal and a relative total shareholder return percentile goal.
(3) Options granted to the Reporting Person under the 2004 Stock Compensation Plan are subject to a four-year vesting schedule. One quarter of the option shares vested on September 13, 2011. The remaining option shares are vesting proportionally each month over the 36 months following September 13, 2011.

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