| Certified Units and Subsidiaries | Location | Date of Certification |
|
| Domestic | |||
| 1 | Takatsuka Unit | Matsudo-shi, Chiba | 11/96 |
| 2 | Akita Unit | Daisen-shi, Akita | 4/97 |
| 3 | Morioka Seiko Instruments Inc. | Iwate-gun, Iwate | 4/97 |
| 4 | Tochigi Unit | Tochigi-shi, Tochigi | 2/98 |
| 5 | SII NanoTechnology Inc. /Oyama Unit | Sunto-gun, Shizuoka | 8/98 |
| 6 | Sendai Unit | Sendai-shi, Miyagi | 2/99 |
| 7 | Ohno Unit | Ichikawa-shi, Chiba | 3/99 |
| 8 | Sukagawa Precision Co., Ltd. | Sukagawa-shi, Fukushima | 9/01 |
| 9 | Makuhari Head Office (Including Business Base) |
Chiba-shi, Chiba | 10/01 |
| Overseas | |||
| 1 | Seiko Instruments Singapore Pte. Ltd. | Singapore | 5/97 |
| 2 | Dalian Seiko Instruments Inc. | Dalian, China | 6/01 |
| 3 | Seiko Instruments (Thailand) Ltd. | Thailand | 3/02 |
| 4 | Instruments Technology (Johor) Sdn. Bhd | Malaysia | 10/02 |
| 5 | Guangzhou Seiko Instruments Ltd. | Guangzhou, China | 7/03 |
| 6 | Guangzhou SII Watch Co., Ltd. | Guangzhou, China | 3/05 |
| 7 | Seiko Instruments (H.K.) Ltd. | Hong Kong | 3/05 |





