| Hydrosonic Limited | Private company limited by shares | Live |
| HYDROSPA LIMITED | Private company limited by shares | Live |
| HydroSpotless Company Limited | Private company limited by shares | Live |
| HYDROSTAR HK LIMITED | Private company limited by shares | Live |
| USA HYDRO-STOP (CHINA) LIMITED | Private company limited by shares | Live |
| HYDROSUN CANADA LIMITED | Private company limited by shares | Live |
| HYDROTEC CO., LIMITED | Private company limited by shares | Dissolved |
| HYDROTEC HYDRAULIC TECHNOLOGY LIMITED | Private company limited by shares | Dissolved |
| HYDROTECH R & D LIMITED | Private company limited by shares | Dissolved |
| HYDRO-TECH LIMITED | Private company limited by shares | Live |
| HYDROTEK COMPANY LIMITED | Private company limited by shares | Dissolved |
| JUST WALK ANIMAL HYDROTHERAPY COMPANY LIMITED | Private company limited by shares | Live |
| Asia Pacific Hydrotherapy Rehabilitation Research Center Limited | Private company limited by shares | Live |
| HYDROHEALTH COLON HYDROTHERAPY LIMITED | Private company limited by shares | Live |
| WATER-CUBE INT'L HYDROTHERAPY PLAN MANAGE GROUP (HK) LIMITED | Private company limited by shares | Dissolved |
| Hong Kong Hydro-therapy Tutor Association Limited | Company limited by guarantee | Live |
| INT'L SWIMMING POOL HYDROTHERAPY GROUP LIMITED | Private company limited by shares | Dissolved |
| OASIS HYDROTHERAPY SYSTEMS LIMITED | Private company limited by shares | Live |
| Germany Slow Old Hydrotherapy Electrical Co., Limited | | Live |
| HydroTide Company Limited | Private company limited by shares | Live |
| Hydroverse Company Limited | | Live |
| HYDROVICTOR HONG KONG LIMITED | Private company limited by shares | Dissolved |
| HYDROWEAR ASIA LIMITED | Private company limited by shares | Live |
| Hydrowise Limited | Private company limited by shares | Live |
| Hydroworks Limited | Private company limited by shares | Live |
| HydroWorld LIMITED | Private company limited by shares | Live |
| HydroX Group Limited | | Live |
| HYDROX (HK) LIMITED | Private company limited by shares | Dissolved |
| HYDROX TECHNOLOGY LIMITED | Private company limited by shares | Dissolved |
| HYDROXY LIMITED | Private company limited by shares | Live |