UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D/A

Under the Securities Exchange Act of 1934

(Amendment No. 3)*

Novatel Wireless, Inc.

(Name of Issuer)

Common Stock, $0.001 Par Value

(Title of Class of Securities)

66987M604

(CUSIP Number)

Bruce A. Karsh

333 South Grand Ave., Suite 2800

Los Angeles, California 90071

213-830-6300

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

February 20, 2015

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.  ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

This Amendment No. 3 (this “Amendment”) amends and supplements the Schedule 13D originally filed with the Securities and Exchange Commission (the “SEC”) on June 2, 2014 and amended on August 14, 2014 and January 26, 2015 (together, this “Schedule 13D”), by Bruce A. Karsh and The Karsh Family Foundation (the “Foundation” and together with Mr. Karsh, the “Reporting Persons”), with respect to the Common Stock, $0.001 par value per share (the “Common Stock”) of Novatel Wireless, Inc. (the “Company”).

Item 3 is hereby amended to add the following:

Since the filing of Amendment No. 2 to this Schedule 13D on January 26, 2015, Mr. Karsh purchased on February 24, 2015 a total of 586,095 shares (the “HC2 Shares”) of the Company’s Common Stock (“Shares”) and a warrant to purchase an additional 293,047 Shares at an exercise price of $2.26 per Share (the “Warrant” and, together with the HC2 Shares, the “Securities”) with personal funds from HC2 Holdings 2, Inc. (“HC2”) in a private transaction for an aggregate purchase price of approximately $1,025,666, or approximately $1.75 per Share plus, in each case, the related Warrant. Also, since the filing of Amendment No. 2 to this Schedule 13D, Mr. Karsh has gifted 500,000 Shares to the Foundation, and the Foundation has sold 325,000 Shares in the open market for aggregate proceeds of approximately $1,629,607.

Item 5 is hereby amended to add the following:

(a) See items 11 and 13 of the cover pages to this Schedule 13D for the aggregate number of Shares and the percentage of the Company’s Common Stock owned by the Reporting Persons. In accordance with Rule 13d-3(d)(1) under the Securities Exchange Act of 1934, the percentage for Mr. Karsh is based upon the 45,902,747 Shares that the Company has informed the Reporting Persons were outstanding as of February 4, 2015, plus the 293,047 Shares underlying the Warrant. The percentage for the Foundation is based upon the 45,902,747 outstanding Shares.

(b) See items 7 through 10 on the cover pages to this Schedule 13D.

(c) The information disclosed in Item 3 with respect to Mr. Karsh’s transaction with HC2 is incorporated herein by reference.

The Foundation made the following open market sales of Shares since the filing of Amendment No. 2 to this Schedule 13D on January 26, 2015:

In addition, on February 23, 2015, Mr. Karsh gifted 500,000 Shares to the Foundation.

Item 6 is hereby amended to add the following:

The information disclosed in Item 3 with respect to Mr. Karsh’s transaction with HC2 is incorporated herein by reference.

The Warrant is being acquired by Mr. Karsh in accordance with Section 7 of the warrant that the Company issued to HC2 on September 8, 2015 (the “Original Warrant”). The terms of the Warrant are substantially similar to the terms of the Original Warrant, which is filed as an Exhibit hereto and is incorporated herein by reference.

In connection with the purchase of the Securities, Mr. Karsh assumed HC2’s rights and obligations with respect to the Securities under the Investors’ Rights Agreement that HC2 entered into with the Company on September 8, 2014 (the “Investors’ Rights Agreement”), except for HC2’s rights under Section 2 of the Investors’ Rights Agreement (which relate to board representation rights).

The Investors’ Rights Agreement provides for, among other things, certain demand and “piggy back” registration rights with respect to the HC2 Shares and the Shares underlying the Warrant. Under the Investors’ Rights Agreement, holders of the majority of the Shares covered by the Investors’ Rights Agreement may cause the Company to register certain Registrable Securities (as defined in the Investors’ Rights Agreement) under the Securities Act of 1933, as amended (the “Securities Act”), and holders of at least 25% of the Shares covered by the Investors’ Rights Agreement may demand that the Company assist in an offering under the Securities Act of all or a portion of the outstanding Registrable Securities, so long as the anticipated aggregate offering price of the securities to be offered is at least $10 million (or such lesser amount representing all remaining Registrable Securities).

The Investors’ Rights Agreement also provides that if the Company decides to register Shares for its own account or the account of any of its stockholders, Mr. Karsh may require the Company to include all or a portion of the HC2 Shares acquired by him or the Shares underlying the Warrant in the registration and, to the extent the registration is in connection with an underwritten public offering, to have such securities included in the offering.

The foregoing is a summary of the material terms of the Investors’ Rights Agreement and is qualified in its entirety by reference to the Investors’ Rights Agreement, which is filed as an Exhibit hereto, and is incorporated herein by reference.

Signature

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.