Page 44 EXHIBIT 21.1 SUBSIDIARY COMPANIES AND STATE OR JURISDICTION OF INCORPORATION All Oceans Drilling B.V. Netherlands 100% Alpha Offshore Drilling Services Cayman Island B.W.I. 100% Atwood Drilling Inc. Delaware 100% Atwood Offshore Inc. Delaware 100% Atwood Hunter Co. Delaware 100% Atwood Oceanics Australia Pty. Ltd. Australia 100% Atwood Oceanics Drilling Company Texas 100% Atwood Oceanics Drilling Pty. Ltd. Australia 100% Atwood Oceanics International, S.A. Panama 100% Atwood Oceanics (M) Sdn. Bhd. Malaysia 100% Atwood Oceanics (NZ) Limited New Zealand 100% Atwood Oceanics Pacific Limited Cayman Island B.W.I. 100% Atwood Oceanics Platforms Pty. Ltd. Australia 100% Atwood Oceanics Service Pty. Ltd. Australia 100% Atwood Oceanics West Tuna Pty. Ltd. Australia 50% Aurora Offshore Services GmbH Germany 100% Clearways Drilling (M) Sdn. Bhd. Malaysia 30% Clearways Offshore Development Drilling Sdn. Bhd. Malaysia 30% Deep Seas Drilling Pty. Ltd. Australia 100% Drillquest (M) Sdn. Bhd. Malaysia 90% Eagle Oceanics, Inc. Delaware 100% Oceandrill (M) Sdn. Bhd. Malaysia 90% PT Pentawood Offshore Drilling Indonesia 80% Swiftdrill, Inc. Texas 100% Swiftdrill Nigeria Limited Nigeria 60%