DIGITAL REALTY TRUST, INC. files 424B7: prospectus (424B)

PROSPECTUS SUPPLEMENT (To Prospectus dated February 17, 2026)

12,310,249 shares Digital Realty Trust, Inc.

Common Stock

The selling stockholders identified in this prospectus supplement are selling 12,310,249 shares of our common stock, $0.01 par value per share (“common stock”), in this offering. We are not selling any shares of common stock under this prospectus supplement and will not receive any proceeds from the sale of shares by the selling stockholders. See “Use of Proceeds.”

We are organized and conduct our operations to qualify as a real estate investment trust (“REIT”), for U.S. federal income tax purposes. To assist us in complying with certain federal income tax requirements applicable to REITs, our charter contains certain restrictions relating to the ownership and transfer of our stock, including an ownership limit of 9.8% (by value or by number of shares, whichever is more restrictive) on the outstanding shares of our common stock.

Our common stock is listed on the New York Stock Exchange under the symbol “DLR”. The last reported sale price of our common stock on the New York Stock Exchange on June 29, 2026 was $190.58 per share.

Investing in our common stock involves risks. See “ Risk Factors ” beginning on page S-5 of this prospectus supplement and the matters discussed in the documents incorporated by reference in this prospectus supplement and the accompanying prospectus.

Neither the U.S. Securities and Exchange Commission (the “SEC”) nor any state securities commission, nor any other regulatory body has approved

(1) Please see the section entitled “Underwriting” for a description of the compensation payable to the underwriter.

The underwriter expects to deliver the shares to purchasers on or about July 1, 2026 through the book-entry facilities of The Depository Trust Company.

Name of Selling Stockholder Number Percentage Number Percentage

(2) Reflects 4,973,529 shares to be held directly by BIP US Nucleus Aggregator L.P., 4,973,470 shares to be held directly by BREP US Nucleus Aggregator L.P., 392,194 shares to be held directly by BXPE Nucleus US Holdco L.P., 34,752 of shares to be held directly by BXPE Nucleus Lux Holdco L.P. and 1,936,304 shares to be held directly by BTO Nucleus Holdings DE L.P. The number of shares offered by each of the foregoing selling stockholders was determined by dividing such dollar amounts by the closing price per share of our common stock on the New York Stock Exchange on June 29, 2026, rounded down to the nearest whole number.

The general partner of BIP US Nucleus Aggregator, L.P. is Blackstone

Infrastructure Associates Non-ECI L.P. The general partner of Blackstone Infrastructure Associates Non-ECI L.P. is BIA GP L.P. The general partner of BIA GP L.P. is BIA

GP L.L.C. The sole member of BIA GP L.L.C. is Blackstone Holdings III L.P. The general partner of Blackstone Holdings III L.P. is Blackstone Holdings III GP Management L.L.C.

The general partner of BREP US Nucleus Aggregator L.P. is BREP US Nucleus Aggregator GP LLC. Blackstone Real Estate Associates X L.P. is the managing member of BREP US Nucleus Aggregator GP LLC. The general partner of Blackstone Real Estate Associates X L.P. is BREA X L.L.C. The managing member of BREA X L.L.C. is Blackstone Holdings II L.P. The general partner of Blackstone Holdings II

L.P. is Blackstone Holdings I/II GP L.L.C.

Blackstone Private Equity Strategies Associates L.P. is the general partner of each of BXPE

Nucleus Lux Holdco L.P. and BXPE Nucleus US Holdco L.P. The general partner of Blackstone Private Equity Strategies Associates L.P. is BXPEA L.L.C. The managing member of BXPEA L.L.C. is Blackstone Holdings II L.P. The general partner of Blackstone

Holdings II L.P. is Blackstone Holdings I/II GP L.L.C.

BTO Holdings Manager IV L.L.C. is the general partner of BTO Nucleus Holdings DE

L.P. The sole member of BTO Holdings Manager IV L.L.C. is BTO DE GP – NQ L.L.C. The sole member of BTO DE GP – NQ L.L.C. is Blackstone Holdings II L.P. The general partner of Blackstone Holdings II L.P. is Blackstone Holdings I/II GP

L.L.C.

Blackstone Inc. is the sole member of Blackstone Holdings I/II GP L.L.C. and Blackstone Holdings III GP Management L.L.C. The sole holder of the Series II preferred stock of Blackstone Inc. is Blackstone Group

Management L.L.C. Blackstone Group Management L.L.C. is wholly-owned by Blackstone’s senior managing directors and controlled by its founder, Stephen A. Schwarzman. Each of the Blackstone entities described in this footnote and Mr. Schwarzman (other than to the extent it or he directly holds securities as described herein) may be deemed to beneficially own the securities directly or indirectly controlled by such Blackstone entities or him, but each disclaims beneficial ownership of such securities. The address of each of such Blackstone entities and Mr. Schwarzman is c/o Blackstone Inc., 345 Park Avenue, New York, New York 10154.

As described under “Prospectus Supplement Summary—Recent Developments,” on June 29, 2026, the company entered into an agreement to purchase from Blackstone all of Blackstone’s interests in the joint ventures. For more information about the company’s relationship with Blackstone and its affiliates, see “Certain Relationships and Related Party

Transactions” in our definitive proxy statement on Schedule 14A, filed with the SEC on April 17, 2026, which is incorporated herein by reference.

UNDERWRITING

Morgan Stanley & Co. LLC is acting as the sole underwriter of the offering. Subject to the terms and conditions set forth in an underwriting agreement among us, the selling stockholders and the underwriter, the selling stockholders have agreed to sell to the underwriter, and the underwriter has agreed to purchase from the selling stockholders, 12,310,249 shares of common stock.

Subject to the terms and conditions set forth in the underwriting agreement, the underwriter has agreed to purchase all of the shares sold under the underwriting agreement if any of these shares are purchased.

We and the selling stockholders have agreed to indemnify the underwriter against certain liabilities, including liabilities under the Securities Act of 1933, as amended (the “Securities Act”), or to contribute to payments the underwriter may be required to make in respect of those liabilities.

The underwriter is offering the shares, subject to prior sale, when, as and if issued to and accepted by it, subject to approval of legal matters by its counsel, including the closing of the Blackstone acquisition, the validity of the shares, and other conditions contained in the underwriting agreement, such as the receipt by the underwriter of officer’s certificates and legal opinions. The underwriter reserves the right to withdraw, cancel or modify offers to the public and to reject orders in whole or in part.