Natural Gas Business Division A
| Company Name | Main Business | Country of Operation |
|---|---|---|
 Brunei LNG Sendirian Berhad |
Manufacturing and sales of LNG | Brunei |
| Brunei Shell Tnakers Sendirian Berhad | Ownership of LNG tankers | Brunei |
| Diamond Gas Resources Pty. Ltd. | Sales agent of JALP crude oil and condensate, reinvestment company | Australia |
| Japan Australia LNG (MIMI) Pty. Ltd. | Development and sales of resources (LNG, LPG, condensate and crude oil) | Australia |
Natural Gas Business Division B
| Company Name | Main Business | Country of Operation |
|---|---|---|
| DIAMOND GAS SAKHALIN B.V. | Stockholding company for Sakhalin Ⅱ project in Russia | The Netherlands |
Petroleum Business Division
| Company Name | Main Business | Country of Operation |
|---|---|---|
| Diamond Tanker Pte. Ltd. | Marine transportation, etc. | Singapore |
| MC Energy, Inc. | Marketing and sales of asphalt and petroleum products | Japan |
| Mitsubishi Shoji Sekiyu Co., Ltd. |
Marketing and sales of petroleum products | Japan |
| Onahama Petroleum Co., Ltd. |
Oil import, storage and sales as well as land and facility leasing | Japan |
| Pacific Orchid Shipping S.A. | Ownership of tankers for transporting crude and heavy oil | Pnanma |
| Petro-Diamond Inc. |
Marketing and sales of petroleum products | U.S.A. |
| Petro-Diamond Japan Corporation | Marketing and sales of petroleum products | Japan |
| Petro-Diamond Singapore (Pte) Ltd. | Marketing and sales of petroleum products | Singapore |
Carbon & LPG Business Division
| Company Name | Main Business | Country of Operation |
|---|---|---|
| Astomos Energy Corporation |
Import, trading, domestic distribution and sales of LPG | Japan |
Exploration & Production Unit
| Company Name | Main Business | Country of Operation |
|---|---|---|
| Ajoco Exploration Co., Ltd. | Development and production of oil in Angola | Japan |
| Ajoco'91 Exploration Co., Ltd. | Development and production of oil in Angola | Japan |
| Angola Japan Oil Co., Ltd. | Exproration, development and production of oil in Angora | Japan |
| ENCORE ENERGY PTE. LTD. | Stockholding company for the company engaged in exploration, development, and production of oil and natural gas mainly in Indonesia | Singapore |
| ENERGI MEGA PRATAMA INC. | Stockholding company for the companies engaged in exploration, development, and production of oil and natural gas in Indonesia | Indonesia |
| MCX Exploration(USA) Ltd. | Exproration, development and sale of oil and natural gas | U.S.A. |
| MPDC Gabon Co., Ltd. | Exproration, development and production of oil in Gabon | Japan |
