EIGHTH SUPPLEMENTAL INDENTURE

EIGHTH SUPPLEMENTAL INDENTURE (this “Eighth Supplemental Indenture”), dated as of July 15, 2013, among Cook Inlet/VS GSM VII PCS Holdings, LLC, a Delaware limited liability company (the “Guaranteeing Subsidiary”), a subsidiary of T-Mobile USA, Inc., a Delaware corporation (“T-Mobile”), T-Mobile, as successor to MetroPCS Wireless, Inc., a Delaware corporation (in such successor capacity, the “Company” pursuant to Section 5.01 of the Indenture referred to herein), the other Guarantors (as defined in the Indenture referred to herein) and Wells Fargo Bank, N.A., as trustee under the Indenture referred to herein (the “Trustee”).

WHEREAS, the Company has heretofore executed and delivered to the Trustee an Indenture, dated as of September 21, 2010 (the “Base Indenture”), among the Company, the Guarantors party thereto and the Trustee, as amended and supplemented in respect of the Company’s 7 7/8% Senior Notes due 2018 (the “2018 Notes”) by the First Supplemental Indenture dated as of September 21, 2010 (the “First Supplemental Indenture”), the Third Supplemental Indenture dated as of December 23, 2010 (the “Third Supplemental Indenture”), the Fifth Supplemental Indenture dated as of December 14, 2012 (the “Fifth Supplemental Indenture”) and the Seventh Supplemental Indenture dated as of May 1, 2013 (the “Seventh Supplemental Indenture”), and as amended and supplemented in respect of the Company’s 7 7/8% Senior Notes due 2020 (together with the 2018 Notes, the “Notes”) by the Second Supplemental Indenture dated as of November 17, 2010 (the “Second Supplemental Indenture”), the Fourth Supplemental Indenture dated as of December 23, 2010 (the “Fourth Supplemental Indenture”), the Sixth Supplemental Indenture dated as of December 13, 2012 (the “Sixth Supplemental Indenture”) and the Seventh Supplemental Indenture (the Base Indenture, as amended and supplemented in respect of the 2020 Notes by the Second Supplemental Indenture, the Fourth Supplemental Indenture, the Sixth Supplemental Indenture and the Seventh Supplemental Indenture, and as amended and supplemented in respect of the 2018 Notes by the First Supplemental Indenture, the Third Supplemental Indenture, the Fifth Supplemental Indenture and the Seventh Supplemental Indenture, the “Indenture”), each among the Company, the Guarantors party thereto and the Trustee;

WHEREAS, the Indenture provides that under certain circumstances the Guaranteeing Subsidiary shall execute and deliver to the Trustee a supplemental indenture pursuant to which the Guaranteeing Subsidiary shall unconditionally guarantee all of the Company’s Obligations under the Notes on the terms and conditions set forth herein (the “Note Guarantee”); and

WHEREAS, pursuant to Section 9.01 of the First Supplemental Indenture as heretofore amended and supplemented and Section 9.01 of the Second Supplemental Indenture as heretofore amended and supplemented, the Trustee is authorized to execute and deliver this Eighth Supplemental Indenture.

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, the Guaranteeing Subsidiary and the

Trustee mutually covenant and agree for the equal and ratable benefit of the Holders of the Notes as follows:

IN WITNESS WHEREOF, the parties hereto have caused this Eighth Supplemental Indenture to be duly executed and attested, all as of the date first above written.