Exhibit 21.1

ATWOOD OCEANICS, INC.

SUBSIDIARY AND AFFILIATED COMPANIES, STATE OR            JURISDICTION OF INCORPORATION AND OWNERSHIP PERCENTAGE

|                                                      |        |        |
|------------------------------------------------------|--------|--------|
| AlphaLeasing Drilling Limited                        |   |   | Mauritius |   |   |   | 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 - Free Zone |   |   | Egypt |   |   |   | 100 | % |
| ATW Management, Inc.                                 |   |   | Delaware |   |   |   | 100 | % |
| Atwood Deep Seas, Ltd. (Partnership)                 |   |   | Texas |   |   |   | 100 | % |
| Atwood Drilling, Inc.                                |   |   | Delaware |   |   |   | 100 | % |
| Atwood Hunter Co.                                    |   |   | Delaware |   |   |   | 100 | % |
| Atwood Management, Inc.                              |   |   | Delaware |   |   |   | 100 | % |
| Atwood Oceanics Australia Pty Limited                |   |   | Australia |   |   |   | 100 | % |
| Atwood Oceanics Drilling Pty                         |   |   | Australia |   |   |   | 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, LP (Partnership)         |   |   | Delaware |   |   |   | 100 | % |
| Atwood Oceanics (NZ) Limited                         |   |   | New Zealand |   |   |   | 100 | % |
| Atwood Oceanics Pacific Limited                      |   |   | Cayman Islands |   |   |   | 100 | % |
| Atwood Oceanics Platforms Pty Ltd.                   |   |   | Australia |   |   |   | 100 | % |
| Atwood Oceanics Services                             |   |   | Singapore |   |   |   | 100 | % |
| Atwood Oceanics Services Pty Ltd.                    |   |   | Australia |   |   |   | 100 | % |
| Atwood Oceanics West Tuna Pty Ltd.                   |   |   | Australia |   |   |   | 100 | % |
| Atwood Offshore Drilling Ltd.                        |   |   | Hong Kong |   |   |   | 100 | % |
| Aurora Offshore Services Gmb                         |   |   | Germany |   |   |   | 100 | % |
| Clearways Offshore Drilling Sdn. Bhd.                |   |   | Malaysia |   |   |   | 49 | % |
| Drillquest (M) Sdn. Bhd.                             |   |   | Malaysia |   |   |   | 100 | % |
| PT Alpha Offshore Drilling                           |   |   | Indonesia |   |   |   | 100 | % |
| PT Pentawood Offshore Drilling                       |   |   | Indonesia |   |   |   | 80 | % |
| Swiftdrill, Inc.                                     |   |   | Cayman Islands |   |   |  | 100 | % |
| Swiftdrill Nigeria Limited                           |   |   | Nigeria |   |   |   | 60 | % |
| Swiftdrill Offshore Drilling Services Company        |   |   | Cayman Islands |   |   |   | 100 | % |