| Blocking Unit |
| 01.12.1941 |
4th and 6th Submarine Squadron (including flag and submarine
tender Chogei) depart Samah, Hainan Island, China. |
| 04.12.1941 |
Light cruiser Kinu (flag 4th Submarine Squadron) departs Samah. |
| 05.12.1941 |
5 Submarine Squadron (including light cruiser Yura)
departs Samah to cover the invasion transports. |
| 08.12.1941 |
4th and 5th Submarine Squadron: Operation 'E' — Invasion of Malaya.
6th Submarine Squadron: Operation 'M' — Invasion of Southern Philippines. |
| 09.12.1941 |
I-123 arrives at Camranh Bay, French Indo-China. |
| 10.12.1941 |
I-124 patroling W of Barigayos Point, western Luzon. |
| 11.12.1941 |
Yura arrives Camranh Bay. |
| 12.12.1941 |
I-121 arrives at Camranh Bay. |
| 12.12.1941 |
I-121 departs Camranh Bay for Davao, Philippines.
13th Submarine Division lays mines NE of Singapore then patrols the eastern entrance to Johore Strait. |
| 13.12.1941 |
5th Submarine Squadron patroling between Natuna Besar Island and NW Borneo
to provide cover for the Second Malaya Convoy and the Japanese landings on North Borneo.
Yura and Kinu depart Camranh, providing cover for the 2nd Malaya Convoy NE of Kuantan. |
| 14.12.1941 |
I-122 and I-124 arrive at Camranh Bay. |
| 15.12.1941 |
I-123 departs Camranh Bay for the Java Sea |
| 17.12.1941 |
Yura and Kinu arrive off Miri,
providing cover for Operation 'B' — The Invasion of British Borneo (Sarawak) |
| 18.12.1941 |
6th Submarine Squadron departs Camranh for Davao on Mindanao, Philippines.
21st Submarine Division departs Sasebo for Camranh Bay, Indochina. |
| 20.12.1941 |
4th Submarine Squadron arrives at Camranh Bay, Indochina. |
| 21.12.1941 |
RO-33 departs Camranh to patrol E of Singapore. |
| 22.12.1942 |
I-124 patrols the entrance to Manila Bay,
then proceeds south via the Mindoro Strait into the Sulu Sea.
Yura and Kinu depart Miri escorting troop transports. |
| 23.12.1941 |
I-123 lays mines at the northern entrance of Surabaya harbor, Java. |
| 23–24.12.41 |
Yura and Kinu provides cover for the
landing at Kuching, Sarawak (British Borneo) |
| 24.12.1941 |
RO-34 arrives at Camranh Bay. |
| 25.12.1941 |
Yura and Kinu departs Kuching. |
| 26.12.1941 |
6 Submarine Squadron reassigned to Southern Force. |
| 27.12.1941 |
5 Submarine Squadron arrive at Camranh Bay.
Yura and Kinu arrive at Camranh Bay. Begins refit until 16.01.42. |
| 28.12.1941 |
19 Submarine Division departs Camranh Bay to patrol off Surabaya, Java.
RO-34 departs Camranh for Karimata Strait. |
| 29.12.1941 |
18 Submarine Division departs Camranh,
but as I-53 and I-54 damaged in heavy seas, both return to Camranh Bay.
I-55 patrols in the Bangka Strait area off Sumatra. |
| 31.12.1941 |
6 Submarine Squadron (including Chogei)
arrives at Davao on Mindanao, Philippines. |
