Exhibit 99.1

Media Contact:

Eric DeRitis, (408) 658-1561

eric.deritis@seagate.com

SEAGATE TECHNOLOGY REPORTS FISCAL FOURTH QUARTER AND FISCAL YEAR 2017 FINANCIAL RESULTS

CUPERTINO, CA – July 25, 2017 – Seagate Technology plc (NASDAQ: STX) (the “Company” or “Seagate”) today reported financial results for the quarter and fiscal year ended June 30, 2017. For the fourth quarter, the Company reported revenue of $2.4 billion, gross margin of 27.7%, net income of $114 million and diluted earnings per share of $0.38. On a non-GAAP basis, which excludes the net impact of certain items, Seagate reported gross margin of 28.9%, net income of $192 million and diluted earnings per share of $0.65.

During the fourth quarter, the Company generated $243 million in cash flow from operations and returned approximately $400 million to shareholders in the form of dividends and share repurchases.

For the fiscal year ended June 30, 2017, the Company reported revenue of $10.8 billion, gross margin of 29.5%, net income of $772 million and diluted earnings per share of $2.58. On a non-GAAP basis, Seagate reported gross margin of 30.5%, net income of $1.2 billion and diluted earnings per share of $4.12.

In fiscal year 2017, the Company generated approximately $1.9 billion in cash flow from operations and returned 53% of that to shareholders in cash dividends of $561 million and share repurchases of 12.1 million ordinary shares for $460 million. Seagate’s balance sheet remains healthy and during the fiscal year the Company successfully raised $1.25 billion in investment-grade debt and repurchased and redeemed approximately $316 million of outstanding debt. Cash and cash equivalents totaled approximately $2.5 billion at the end of the fiscal year. There were 292 million ordinary shares issued and outstanding as of the end of the fiscal year.

“The results of our performance this fiscal year reflect improved year-over-year profitability of our storage product portfolio and business operations,” said Steve Luczo, Seagate’s chairman and chief executive officer. “Although the near-term dynamics of technology shifts present demand variations for the storage industry from time to time, we continue to see growing storage demand in the long-run driven by the proliferation of data growth from new technologies, emerging industries, and growing businesses. We believe we have the vision, products, technology and experience to ensure our long-term success and shareholder value.”

For a detailed reconciliation of GAAP to non-GAAP results, see accompanying financial tables.

Seagate has issued a Supplemental Financial Information document, which is available on Seagate’s Investors Relations website at www.seagate.com/investors.

Quarterly Cash Dividend

The Board of Directors of the Company (the “Board”) has approved a quarterly cash dividend of $0.63 per share, which will be payable on October 4, 2017 to shareholders of record as of the close of business on September 20, 2017. The payment of any future quarterly dividends will be at the discretion of the Board and will be dependent upon Seagate’s financial position, results of operations, available cash, cash flow, capital requirements and other factors deemed relevant by the Board.

Investor Communications

Seagate management will hold a public webcast today at 6:00 a.m. Pacific Time that can be accessed on its Investor Relations website at www.seagate.com/investors. During today’s webcast, the Company will provide an outlook for its first fiscal quarter of 2018, including key underlying assumptions.

An archived audio webcast of this event will be available on Seagate’s Investors Relations website at www.seagate.com/investors shortly following the event conclusion.

About Seagate

To learn more about the Company’s products and services, visit www.seagate.com and follow us on Twitter, Facebook, LinkedIn, Spiceworks, YouTube and subscribe to our blog. The contents of our website and social media channels are not a part of this release.

Cautionary Note Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, each as amended, including, in particular, statements about the Company’s plans, strategies and prospects, financial projections, estimates of industry growth, market demand, shifts in technology and dividend issuance plans for the fiscal quarter ending September 29, 2017 and beyond. These statements identify prospective information and may include words such as “expects,” “intends,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “projects,” “should,” “may,” “will,” or the negative of these words, variations of these words and comparable terminology. These forward-looking statements are based on information available to the Company as of the date of this report and are based on management’s current views and assumptions. These forward-looking statements are conditioned upon and also involve a number of known and unknown risks, uncertainties, and other factors that could cause actual results, performance or events to differ materially from those anticipated by these forward-looking statements. Such risks, uncertainties, and other factors may be beyond the Company’s control and may pose a risk to the Company’s operating and financial condition. Such risks and uncertainties include, but are not limited to: items that may be identified during its financial statement closing process that cause adjustments to the estimates included in this report; the uncertainty in global economic conditions; the impact of the variable demand and adverse pricing environment for disk drives; the Company’s ability to successfully qualify, manufacture and sell its disk drive products in increasing volumes on a cost-effective basis and with acceptable quality; the impact of competitive product announcements; the Company’s ability to achieve projected cost savings in connection with restructuring plans; possible excess industry supply with respect to particular disk drive products; disruptions to its supply chain or production capabilities; unexpected advances in competing technologies or changes in market trends; the development and introduction of products based on new technologies and expansion into new data storage markets; the Company’s ability to comply with certain covenants in its credit facilities with respect to financial ratios and financial condition tests; currency fluctuations that may impact the Company’s margins and international sales; cyber-attacks or other data breaches that disrupt the Company’s operations or results in the dissemination of proprietary or confidential information and cause reputational harm; and fluctuations in interest rates. Information concerning risks, uncertainties and other factors that could cause results to differ materially from the expectations described in this press release is contained in the Company’s Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission on August 5, 2016, the “Risk Factors” section of which is incorporated into this press release by reference, and other documents filed with or furnished to the Securities and Exchange Commission. These forward-looking statements should not be relied upon as representing the Company’s views as of any subsequent date and the Company undertakes no obligation to update forward-looking statements to reflect events or circumstances after the date they were made.

The inclusion of Seagate’s website address in this press release is intended to be an inactive textual reference only and not an active hyperlink. The information contained in, or that can be accessed through, Seagate’s website and social media channels are not part of this press release.

SEAGATE TECHNOLOGY PLC

CONDENSED CONSOLIDATED BALANCE SHEETS

(In millions)

(Unaudited)

SEAGATE TECHNOLOGY PLC

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(In millions, except per share data)

(Unaudited)

SEAGATE TECHNOLOGY PLC

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(In millions)

(Unaudited)

Use of non-GAAP financial information

The Company uses non-GAAP measures of adjusted revenue, gross margin, net income, diluted earnings per share and operating expenses which are adjusted from results based on GAAP to exclude certain expenses, gains and losses. These non-GAAP financial measures may be provided to enhance the user’s overall understanding of the Company’s current financial performance and its prospects for the future. Specifically, the Company believes non-GAAP results provide useful information to both management and investors as these non-GAAP results exclude certain expenses, gains and losses that it believes are not indicative of its core operating results and because it is similar to the approach used in connection with the financial models and estimates published by financial analysts who follow the Company.

These non-GAAP results are some of the primary measurements management uses to assess the Company’s performance, allocate resources and plan for future periods. Reported non-GAAP results should only be considered as supplemental to results prepared in accordance with GAAP, and not considered as a substitute for, or superior to, GAAP results. These non-GAAP measures may differ from the non-GAAP measures reported by other companies in its industry.

SEAGATE TECHNOLOGY PLC

ADJUSTMENTS TO GAAP NET INCOME AND DILUTED NET INCOME PER SHARE

(In millions, except per share amounts)

(Unaudited)