Exhibit 21.1

ATWOOD OCEANICS, INC.

SUBSIDIARY AND AFFILIATED COMPANIES, STATE OR

JURISDICTION OF INCORPORATION AND OWNERSHIP PERCENTAGE

Alpha Achiever Company	Cayman Islands	100	%
Alpha Advantage Company	Cayman Islands	100	%
Alpha Aurora Company	Cayman Islands	100	%
Alpha Beacon Company	Cayman Islands	100	%
Alpha Condor Company	Cayman Islands	100	%
Alpha Falcon Company	Cayman Islands	100	%
Alpha Falcon Drilling Company	Cayman Islands	100	%
Alpha Hunter Company	Cayman Islands	100	%
Alpha International Drilling Company S.a.r.l.	Luxembourg	100	%
Alpha Leasing Drilling Limited	Mauritius	100	%
Alpha Mako Company	Cayman Islands	100	%
Alpha Manta Company	Cayman Islands	100	%
Alpha Offshore Drilling (Cambodia) Ltd.	Cambodia	100	%
Alpha Offshore Drilling (S) Pte. Ltd.	Singapore	100	%
Alpha Offshore Drilling Services Company	Cayman Islands	100	%
Alpha Offshore Drilling Services Company, Limited	Angola	100	%
Alpha Offshore Drilling Services Company (Ghana) Ltd.	Ghana	100	%
Alpha Offshore International Leasing Limited	UK	100	%
Alpha Offshore Mexico Company, S. de. R.L. de C.V.	Mexico	100	%
Alpha Offshore Mexico Labor Company, S. de. R.L. de C.V.	Mexico	100	%
Alpha Offshore Singapore Supply Company Pte. Ltd.	Singapore	100	%
Alpha Orca Company	Cayman Islands	100	%
Alpha Osprey Company	Cayman Islands	100	%
Alpha Seahawk Company	Cayman Islands	100	%
Alpha Singapore Supply Company Pte. Ltd.	Singapore	100	%
Alpha South Pacific Holding Company	Western Australia	100	%
Alpha Southern Cross Pty. Ltd.	Western Australia	100	%
Alpha Vicksburg Pty. Ltd.	Western Australia	100	%
ATW Management, Inc.	Delaware	100	%
Atwood Australian Waters Drilling Pty. Ltd.	Western Australia	100	%
Atwood Deep Seas, Ltd.	Texas	100	%
Atwood Drilling, Inc.	Delaware	100	%
Atwood Hunter Co.	Delaware	100	%
Atwood Malta Holding Company Limited	Malta	100	%
Atwood Management, Inc.	Delaware	100	%
Atwood Oceanics Australia Pty. Ltd.	Western Australia	100	%

ATWOOD OCEANICS, INC.

SUBSIDIARY AND AFFILIATED COMPANIES, STATE OR

JURISDICTION OF INCORPORATION AND OWNERSHIP PERCENTAGE

Atwood Oceanics Drilling Pty. Ltd.	Western Australia	100	%
Atwood Oceanics Global Limited	Cayman Islands	100	%
Atwood Oceanics International Limited	Cayman Islands	100	%
Atwood Oceanics Leasing Ltd.	Malaysia	100	%
Atwood Oceanics (M) Sdn. Bhd.	Malaysia	100	%
Atwood Oceanics Malta Ltd.	Malta	100	%
Atwood Oceanics Management, L.P.	Delaware	100	%
Atwood Oceanics (NZ) Limited	New Zealand	100	%
Atwood Oceanics Pacific Limited	Cayman Islands	100	%
Atwood Oceanics Platforms Pty. Ltd.	Western Australia	100	%
Atwood Oceanics Services Pty. Ltd.	Western Australia	100	%
Atwood Oceanics West Tuna Pty. Ltd.	Western Australia	100	%
Atwood Offshore Drilling Ltd.	Hong Kong	100	%
Atwood Offshore Worldwide Limited	Cayman Islands	100	%
Atwood Serviços de Perfuração Ltda.	Brazil	100	%
Aurora Offshore Services GmbH	Germany	100	%
Clearways Offshore Drilling Sdn. Bhd.	Malaysia	49	%
Drillquest International Offshore Drilling Services Company	Cayman Islands	100	%
Drillquest Offshore Company	Cayman Islands	100	%
Pacific Offshore Labor Company	Cayman Islands	100	%
PT Alpha Offshore Drilling	Indonesia	100	%
PT Pentawood Offshore Drilling	Indonesia	80	%
Swiftdrill, Inc.	Cayman Islands	100	%
Swiftdrill Malta	Malta	100	%
Swiftdrill Nigeria Limited	Nigeria	60	%
Swiftdrill Offshore Drilling Services Company	Cayman Islands	100	%