| SEA DRILL LIMITED | Private company limited by shares | Dissolved |
| DRILL COMPANY LIMITED | Private company limited by shares | Live |
| SUN DRILL LIMITED | Private company limited by shares | Live |
| HYDRO DRILL LIMITED | Private company limited by shares | Dissolved |
| Drill Point Limited | Private company limited by shares | Live |
| SMART DRILL LIMITED | Private company limited by shares | Live |
| DRILL TEAM 162 LIMITED | Private company limited by shares | Live |
| DRILL TRADE LIMITED | Private company limited by shares | Dissolved |
| DRILLCHEM (H.K.) LIMITED | Private company limited by shares | Dissolved |
| DRILLCUT LIMITED | Private company limited by shares | Live |
| Top Driller Limited | Private company limited by shares | Live |
| Oil Driller Equipment Co., Limited | Private company limited by shares | Live |
| Ocean Driller III Limited | Private company limited by shares | Live |
| Ocean Driller II Limited | Private company limited by shares | Live |
| Ocean Driller I Limited | Private company limited by shares | Live |
| DRILLER'S EQUIPMENT (H.K.) LIMITED | Private company limited by shares | Dissolved |
| DRILLERS INTERNATIONAL COMPANY LIMITED | Private company limited by shares | Dissolved |
| UNITED DRILLERS LIMITED | Private company limited by shares | Dissolved |
| KO KIM DRILLING LIMITED | Private company limited by shares | Live |
| LEE WAH DRILLING COMPANY LIMITED | Private company limited by shares | Live |
| KPC Drilling Limited | Private company limited by shares | Live |
| ACS DRILLING LIMITED | Private company limited by shares | Live |
| Sun Fai Drilling Limited | | Live |
| ADVANCED DRILLING FLUIDS LIMITED | Private company limited by shares | Live |
| COMPANION DRILLING COMPANY LIMITED | Private company limited by shares | Live |
| Eastern Drilling HK Limited | Private company limited by shares | Live |
| EXCELLENT DRILLING LIMITED | Private company limited by shares | Live |
| DRILLING INNOVATION LIMITED | Private company limited by shares | Dissolved |
| Keep Drilling Limited | | Live |
| KOLIC DRILLING COMPANY LIMITED | Private company limited by shares | Dissolved |
| DRILLING PROJECTS LIMITED | Private company limited by shares | Dissolved |
| SMART DRILLING (ASIA) LIMITED | Private company limited by shares | Live |
| DRILLING SOLUTIONS LIMITED | Private company limited by shares | Live |
| H&C Drilling Supply Limited | Private company limited by shares | Live |
| DRILLING SYSTEMS LIMITED | Private company limited by shares | Live |
| NORTHERN DRILLINGS LIMITED | Private company limited by shares | Dissolved |
| JIANGSU FEIDA DRILLS CO., LIMITED | Private company limited by shares | Live Commenced dormancy on 09-Apr-2015 |
| DRILLTECH LIMITED | Private company limited by shares | Live |
| ADVANCED DRILLTEST LIMITED | Private company limited by shares | Dissolved |
| DRILLTOOL SERVICES LIMITED | Private company limited by shares | Dissolved |
| DRILLWELL LIMITED | Private company limited by shares | Live |