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 * O MALLEY PATRICK J   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 & Chief Financial Officer (Last) (First) (Middle) SEAGATE TECHNOLOGY PLC, 10200 S. DE ANZA BOULEVARD 3. Date of Earliest Transaction (Month/Day/Year) 11/21/2012 (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 11/21/2012   M   3,954 A $ 13.73 412,566.65 D   Ordinary Shares 11/21/2012   M   31,774 A $ 3.345 444,340.65 D   Ordinary Shares 11/21/2012   M   54,166 A $ 11.065 498,506.65 D   Ordinary Shares 11/21/2012   S(1)   57,280 D $ 26.7746 (2) 441,226.65 D

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

NQ Stock Options

$ 13.73

11/21/2012

M

3,954

09/12/2009(3)

09/12/2015

Ordinary Shares

3,954

$ 0

0

D

NQ Stock Options

$ 3.345

11/21/2012

M

31,774

09/11/2010(4)

03/06/2016

Ordinary Shares

31,774

$ 0

109,683

D

NQ Stock Options

$ 11.065

11/21/2012

M

54,166

09/13/2011(5)

09/13/2017

Ordinary Shares

54,166

$ 0

45,834

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
O MALLEY PATRICK J SEAGATE TECHNOLOGY PLC 10200 S. DE ANZA BOULEVARD CUPERTINO, CA 95014			EVP & Chief Financial Officer

Signatures

/s/ Roberta S. Cohen by power of attorney		11/26/2012
**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)	This transaction is a "sell to cover" transaction in which the Reporting Person used the proceeds from the sale of shares in part to fund the exercise of the options.
(2)	The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at sales prices ranging from $26.62 to $27.00, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
(3)	Options granted to the Reporting Person under the Issuer's 2004 Stock Compensation Plan are subject to a four-year vesting schedule. One quarter of the option shares vested on September 12, 2009. The remaining option shares vest in equal monthly installments over the 36 months following September 12, 2009.
(4)	Options granted to the Reporting Person under the Issuer's 2004 Stock Compensation Plan are subject to a four and a half year vesting schedule. One quarter of the option shares vested on September 11, 2010. Following continuous employment, the remaining option shares vest in equal monthly installments over the 36 months following September 11, 2010.
(5)	Options granted to the Reporting Person under the Issuer's 2001 Share Option Plan are subject to a four-year vesting schedule. One quarter of the option shares vested on September 13, 2011. The remaining option shares vest in equal monthly installments over the 36 months following September 13, 2011.

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