| 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 |