Exhibit 21.1
Subsidiaries of the Registrant

Entity NameState or Country of Incorporation or Organization
AC First, LLCDelaware
Aeroptic, LLCMassachusetts
Aerospace Testing AllianceTennessee
Afghan Holdco LLCDelaware
Africa Expeditionary Services LLCDelaware
AGS Sudan LimitedSouth Sudan
Airport & MRO Facilities Nigeria LimitedNigeria
Amazon Finance LLCDelaware
Amentum (UK) Ltd.United Kingdom
Amentum Australia Pty LimitedAustralia
Amentum Brazil LtdaSao Paulo
Amentum Business Support Services Inc.Philippines
Amentum Clean Energy France SAS (U.K.)France
Amentum Clean Energy International LimitedUnited Kingdom
Amentum Clean Energy LimitedUnited Kingdom
Amentum Clean Energy s.r.oCzech Republic
Amentum Commercial Operations, Inc.Delaware
Amentum Digital Infrastructure, Inc.New Jersey
Amentum E&C LimitedUnited Kingdom
Amentum Enterprise Asset Solutions Construction LimitedUnited Kingdom
Amentum Enterprise Asset Solutions LimitedUnited Kingdom
Amentum Environment & Energy, Inc.Ohio
Amentum Facility Management UK Ltd.United Kingdom
Amentum Global Services - Australia Pty LtdAustralia
Amentum GmbHGermany
Amentum Government Services Holdings LLCDelaware
Amentum Government Services Holdings Sub LLCDelaware
Amentum Government Services Parent Holdings LLCDelaware
Amentum Government Services, Inc.Delaware
Amentum Holdings LLCDelaware
Amentum IDC SARLFrance
Amentum International Holdings UK Ltd.United Kingdom
Amentum International Nuclear Services LtdUnited Kingdom
Amentum Japan K.K.Japan
Amentum Mitie Pacific LLCDelaware
Amentum Multiconsult Decommissioning ANSNorway
Amentum N&E Holdings LLCDelaware
Amentum N&E UK Holdings LimitedUnited Kingdom
Amentum National Security Programs, Inc.Virginia
Amentum New York Inc.New York
Amentum Nuclear & Environment Holdings, Inc.Delaware
Amentum Operaciones ComercialesMexico
Amentum Operaciones Comerciales CRCosta Rica
Amentum Parsons Logistics Services LLCDelaware
Amentum Services Canada, Inc.Canada
Amentum Services Colombia S.A.S.Colombia
Amentum Services SDN. BHD.Malaysia
Amentum Services, Inc.Delaware
Amentum Singapore Pte. Ltd.Singapore
Amentum Slovakia s.r.o.Slovakia
Amentum South Africa PTY Ltd.South Africa
Amentum Spaceport LLCDelaware
Amentum Special Mission Services, Inc.Pennsylvania
Amentum SPV LLCDelaware
Amentum SRLArgentina



Amentum Technical Services LLCDelaware
Amentum Technology, Inc.Tennessee
Augility Pty LimitedAustralia
Augility Services Pty LimitedAustralia
Automotive Testing Operations, LLCDelaware
Avicom do Brasil Manutencao de Aeronaves LtdaBrazil
Blue Canopy Group, LLCVirginia
Bravour Leistungen GmbHGermany
Buffalo Group LLCDelaware
Carondelet Energy Readiness LLCDelaware
Casals & Associates, Inc.Virginia
Centra Services CorporationMassachusetts
Centra Technology, Inc.Maryland
Central Plateau Cleanup Company LLCDelaware
CH2M Hill BWXT West Valley, L.L.CDelaware
CH2M HILL Plateau Remediation CompanyWashington
CH2M-WG Idaho, LLCIdaho
Courage Services, Inc.Virginia
Critical Mission Services sp. z.o.oPoland
Culpeper National Security Solutions LLCDelaware
Cumbria Nuclear Solutions LimitedUnited Kingdom
D2R Services LLCDelaware
Defense Support Services International 3 LLCDelaware
Defense Support Services International, LLCDelaware
Delta Bridge, Inc.Virginia
DTS Aviation Services LLCNevada
DynCorp Aerospace Operations LLCDelaware
DynCorp International Business Services Private LimitedIndia
DynCorp International LLCDelaware
DynCorp International Services GmbHGermany
DynCorp International Services LLCVirginia
DynCorp LLCDelaware
DZSP 21 LLCDelaware
DZSP 22 LLCDelaware
EG&G Defense Materials, Inc.Utah
Energy, Safety & Risk Consultants (UK) LimitedUnited Kingdom
Energy, Security and Technology Canada Ltd.Canada
Energy, Security and Technology LLC (dba ES&T North America)Delaware
Energy, Security and Technology UK LimitedUnited Kingdom
Equitas International LLCDelaware
Expeditionary Logistics Services LLCEgypt
Expeditionary Services Benin LLCCotonou
Fast Reactor Technology LimitedUnited Kingdom
Federal Network Systems LLCDelaware
Four Rivers Nuclear Partnership, LLCDelaware
Future Investment Group LLCEgypt
GL Systems LLCDelaware
Global Linguist Solutions LLCDelaware
Global Linguist Solutions Turkey Tercüme Hizmetleri Limited ŞirketiTurkey
Global Management Services GmbHGermany
Global Sourcing SolutionsCayman Islands
Greenline Systems Canada UlcCanada
Idaho Environmental Coalition LLCDelaware
InSpace 21 LLCDelaware
JT4, LLCDelaware
Lear Siegler Logistics International, Inc.Delaware
Macfadden & Associates, Inc.Virginia
Macfadden International SuarlTunisia
McNeil Security, Inc.Virginia



Momentum SNCFrance
MS Federal Services, Inc.Nevada
MSFS Holdings US, Inc.Nevada
MT Holding Corp.Delaware
National Nuclear Corporation LimitedUnited Kingdom
NEXTGEN-H Integration Services LLCDelaware
Nuclear Waste Partnership LLCDelaware
Pacific Architects and Engineers, LLCDelaware
Pacific Operations Maintenance CompanyCalifornia
Pacific Research Support LLCDelaware
PAE (Australia) Pty. LimitedAustralia
PAE Applied Technologies International LLCDelaware
PAE Applied Technologies LLCDelaware
PAE Canada, Inc.California
PAE Colombia Ltda.Colombia
PAE Design and Facility ManagementCalifornia
PAE FoundationBosnia and Herzegovina
PAE Global Support LLCDelaware
PAE Government Services Colombia S.A.S.Colombia
PAE Government Services Mexico, S. De R.L. De C.V.Mexico
PAE Government Services, Inc.California
PAE Humanitarian Response LLCDelaware
PAE India Support Center LLPIndia
PAE InternationalCalifornia
PAE ISR LLCDelaware
PAE Justice SupportVirginia
PAE LLCDelaware
PAE Logistics LLCCalifornia
PAE Services Canada Inc.Canada
PAE Shared Services LLCDelaware
PAE Shield Acquisition Company LLCDelaware
PAE Training Services, LLCDelaware
PAE Worldwide IncorporatedDelaware
PAE-Perini LLCDelaware
Phoenix Consulting Group, LLCAlabama
PWR Power Projects LimitedUnited Kingdom
Quality Systems Engineering Consortium, LLCCalifornia
Reagan Redstone Range Alliance LLCDelaware
Rocky Mountain Remediation Services LLCColorado
Safe Sites of Colorado LLCDelaware
Savannah River Remediation LLCDelaware
Service Systems (Singapore) Pte. Ltd.Singapore
Services International LLCDelaware
Sotera Defense Solutions, Inc.Delaware
Southern Ohio Cleanup Company LLCDelaware
Space Coast Launch Services LLCNevada
Syncom Space Services LLCDelaware
TATE, IncorporatedMaryland
The KeyW CorporationMaryland
The KeyW Holding CorporationMaryland
Triple20 LLCMaryland
UCOR LLCTennessee
United Cleanup Oak Ridge LLCDelaware
URS Federal Services International, Inc.Delaware
USA Repository Services LLCDelaware
Washington Closure Hanford LLCDelaware
Washington Demilitarization Company, LLCDelaware
Washington Government Environmental Services Company LLCDelaware
Washington River Protection Solutions LLCDelaware



Washington Savannah River Company LLCDelaware
Washington TRU Solutions LLCNew Mexico
West Valley Nuclear Services Company LLCDelaware
WGI Global Inc.Nevada
Worldwide For General Services, Construction And Engineering Services And Subsistence Services LLC Iraq
Worldwide Management and Consulting Services LLCDelaware
Worldwide Recruiting and Staffing Services LLCDelaware