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

PROSPECTUS SUPPLEMENT (To Prospectus dated February 17, 2026)

696,060 Digital Realty Trust, Inc.

Common Stock

This prospectus supplement relates to the potential resale from time to time by the selling stockholders identified in this prospectus supplement of some or all of 696,060 shares of our common stock, $0.01 par value per share (“common stock”). The registration of the shares of common stock covered by this prospectus supplement does not necessarily mean that any of the shares will be offered or sold by the selling stockholders. The selling stockholders acquired the shares of common stock on August 19, 2026 pursuant to the transactions contemplated in that certain purchase agreement dated May 8, 2026, by and among us, Digital Cloud Holding, LLC, Columbia Capital GP, LLC, the selling stockholders named therein and James B. Fleming, Jr., as seller representative (the “Purchase Agreement”). We issued the shares in reliance upon the exemption from registration afforded by Section 4(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”), and are registering such shares pursuant to the Columbia Capital Registration Rights Agreement (as defined below). For information regarding the selling stockholders, please refer to the section entitled “Selling Stockholders” on page S-4 of this prospectus supplement.

We are not selling any shares of common stock under this prospectus supplement and will not receive any proceeds from the resale of shares by the selling stockholders, but we have agreed to pay certain registration expenses. See “Use of Proceeds.”

The selling stockholders identified in this prospectus supplement (which term as used herein includes their pledgees, donees, transferees, or other successors in interest), may offer the securities from time to time as they may determine directly or through underwriters, broker-dealers or agents and in one or more public or private transactions and at fixed prices, prevailing market prices, at prices related to prevailing market prices or at negotiated prices. If the securities are sold through underwriters, broker-dealers or agents, the selling stockholders will be responsible for underwriting discounts or commissions or agents’ commissions. See the sections entitled “Plan of Distribution” and “About this Prospectus Supplement and the Prospectus”

for more information.

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 August 18, 2026 was $195.25 per share.

Investing in our common stock involves risks. See “ Risk Factors ” beginning on page S-2 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

Name of Selling Stockholder Number Percentage Number Percentage

Donald A. Doering Revocable Trust 48,974 * 14,692 34,282 *

James B. Fleming, Jr. 568,395 * 170,519 397,876 *

Jason R. Booma 396,914 * 119,074 277,840 *

John T. Siegel, Jr. 447,284 * 134,185 313,099 *

Patrick B. Hendy 409,886 * 122,966 286,920 *

* less than 1%

(1) Represents the number of shares of common stock being registered on behalf of each selling stockholder pursuant to this prospectus supplement. The amounts set forth in this column do not include any other shares of common stock that each selling stockholder may own beneficially or otherwise.

(2) Assumes that the selling stockholders dispose of all of the shares of common stock covered by this prospectus supplement and do not acquire beneficial ownership of any additional shares.

(3) The shares are held by the Donald A. Doering Revocable Trust. Donald A. Doering is the sole trustee of the Donald A. Doering Revocable Trust and has sole voting and dispositive power with respect to the shares held by the trust.

PLAN OF DISTRIBUTION

The selling stockholders, or their pledgees, donees, transferees, or any of their successors in interest selling the securities received from a named selling stockholder after the date of this prospectus supplement (all of whom may be selling stockholders), may sell the securities from time to time on any stock exchange or automated interdealer quotation system on which the securities are traded, in the over-the-counter market, in privately negotiated transactions or otherwise, at fixed prices that may be changed, at market prices prevailing at the time of sale, at prices related to prevailing market prices or at prices otherwise negotiated. The selling stockholders may sell the securities by one or more of the following methods, without limitation:

• block trades in which the broker or dealer so engaged will attempt to sell the securities as agent but may position and resell a portion of the block as principal to facilitate the transaction, or in crosses in which the same broker acts as agent on both sides;

• purchases by a broker or dealer as principal and resale by the broker or dealer for its own account pursuant to this prospectus supplement;

• privately negotiated transactions;

• short sales;

• through the writing of options on the securities, swaps or other derivatives, whether or not the options or such instruments are listed on an exchange;

• only upon our prior consent, one or more underwritten offerings on a firm commitment or best efforts basis or other purchases by underwriters, brokers, dealers, and agents who may receive compensation in the form of underwriting discounts, concessions or commissions from the selling stockholders and/or the purchasers of the securities for whom they may act as agent;

• pledges of the securities as security for any loan or obligation, including pledges to brokers or dealers who may from time to time effect distributions of the securities;

• sales in other ways not involving market makers or established trading markets, including direct sales to institutions or individual purchasers; or

• any combination of the foregoing methods or by any other legally available means.

The selling stockholders may also transfer the securities by gift. We do not know of any arrangements by the selling stockholders for the sale of any of the securities.