# Southern Expeditionary Fleet (Imperial Japanese Navy)

The Southern Expeditionary Fleet (南遣艦隊, Nanken Kantai) was a fleet of the Imperial Japanese Navy, their roles were invasion and maintenance of the public order in southwestern area the French Indochina, Philippines, British Malaya and Dutch East Indies.

## Organization
### Southern Expeditionary Fleet/1st Southern Expeditionary Fleet

The Southern Expeditionary Fleet was organized for Invasion of French Indochina on 31 July 1941. Describe the 1st Southern Expeditionary Fleet (第一南遣艦隊, Dai-Ichi Nanken Kantai) also. Their jurisdiction area was French Indochina, Singapore and westward.
* Structure (extract)
| Date | Highest unit | Higher unit | Fleet name | Lower units, vessels and elements |
| 31 July 1941 (original) | Imperial General Headquarters | | Southern Expeditionary Fleet | Cruiser Kashii, Coast defence ship Shimushu |
| 10 December 1941 | Combined Fleet | | Southern Expeditionary Fleet | Cruiser Kashii, Coast defence ship Shimushu, 9th Base Force, 11th Special Base Force |
| 3 January 1942 | Combined Fleet | | 1st Southern Expeditionary Fleet (renamed) | Cruiser Kashii, Coast defence ship Shimushu, 9th Base Force, 11th Special Base Force |
| 10 April 1942 | Combined Fleet | Southwest Area Fleet | 1st Southern Expeditionary Fleet | Cruiser Kashii, Coast defence ship Shimushu, Minelayer Katsuriki, C.M. Seaplane tender Sagara Maru, 5th Destroyer Division, 9th Base Force, 10th Special Base Force, 11th Special Base Force, 12th Special Base Force, 40th Naval Air Group, 3rd Surveying Unit |
| 1 November 1942 | Combined Fleet | Southwest Area Fleet | 1st Southern Expeditionary Fleet | Cruiser Kashii, Escort ship Shimushu, Survey ship Katsuriki, C.M. Seaplane tender Sagara Maru, 5th Destroyer Division, 9th Special Base Force, 10th Special Base Force, 11th Special Base Force, 12th Special Base Force, 936th Naval Air Group, 3rd Surveying Unit |
| 15 August 1944 | Combined Fleet | Southwest Area Fleet | 1st Southern Expeditionary Fleet | Minelayer Yaeyama, Destroyer Amatsukaze 9th Special Base Force, 10th Special Base Force, 11th Special Base Force, 12th Special Base Force, 13th Special Base Force, 15th Base Force, 11th Naval Air Group, 12th Naval Air Group, 13th Naval Air Group, 936th Naval Air Group |
| 5 February 1945 | Combined Fleet | 10th Area Fleet | 1st Southern Expeditionary Fleet | Cruiser Myōkō, Takao, Destroyer Amatsukaze, Auxiliary submarine chaser No. 59, 9th Special Base Force, 10th Special Base Force, 11th Special Base Force, 12th Special Base Force, 13th Special Base Force, 15th Base Force |
| 12 September 1945 | Surrendered. | Surrendered. | Surrendered. | Surrendered. |
* Commander in chief
| | Rank | Name | Date | Note, additional post |
| 1 | Vice-Admiral | Noboru Hirata | 31 July 1941 | |
| 2 | Vice-Admiral | Jisaburō Ozawa | 18 October 1941 | |
| 3 | Vice-Admiral | Denshichi Ōkawachi | 14 July 1942 | |
| 4 | Vice-Admiral | Minoru Tayui | 20 September 1943 8 January 1945 | Commander in chief of the 13th Air Fleet |
| 5 | Vice-Admiral | Shigeru Fukudome | 13 January 1945 5 February 1945 | Commander in chief of the 13th Air Fleet Commander of the 10th Area Fleet and 13th Air Fleet |
* Chief of staff
| | Rank | Name | Date | Note, additional post |
| 1 | Captain Rear-Admiral | Torao Sawada | 31 July 1941 15 October 1941 | |
| 2 | Captain Rear-Admiral | Kiyoshi Hamada | 20 June 1942 1 November 1942 | |
| 3 | Rear-Admiral | Shin'ichi Torigoe | 27 August 1943 | |
| 4 | Rear-Admiral | Bunji Asakura | 16 August 1944 8 January 1945 5 February 1945 | Chief of staff of the 13th Air Fleet Chief of staff of the 10th Area Fleet and 13th Air Fleet |

### 2nd Southern Expeditionary Fleet

The 2nd Southern Expeditionary Fleet (第二南遣艦隊, Dai-Ni Nanken Kantai) was reorganized from 3rd Fleet on 10 March 1942. Describe 3rd Fleet about predecessor of the 2nd Southern Expeditionary Fleet. Their jurisdiction area was Dutch East Indies.
* Structure (extract)
| Date | Highest unit | Higher unit | Fleet name | Lower units, vessels and elements |
| 10 April 1941 (original) | Combined Fleet | | 3rd Fleet | 16th Division, 17th Division, 5th Torpedo Division, 12th Air Flotilla, 1st Base Force, 2nd Base Force |
| 10 December 1941 | Combined Fleet | | 3rd Fleet | 16th Division, 17th Division, 5th Torpedo Division, 6th Submarine Squadron, 12th Air Flotilla, 1st Base Force, 2nd Base Force, 32nd Special Base Force, C.M. Repair ship Yamabiko Maru, C.M. Water supply ship Kōan Maru, C.M. Freighter Senkō Maru |
| 10 March 1942 | Combined Fleet | Southwest Area Fleet | 2nd Southern Expeditionary Fleet (renamed and reorganized) | Cruiser Ashigara, Minelayer Itsukushima, Survey ship Tsukushi, 16th Division, 2nd Gunboat Division, 21st Special Base Force, 22nd Special Base Force, 23rd Special Base Force, 24th Special Base Force, C.M. Seaplane tender San'yō Maru, 9th Surveying Unit |
| 1 September 1943 | Combined Fleet | Southwest Area Fleet | 2nd Southern Expeditionary Fleet | Minelayer Itsukushima, Patrol boat No. 102, No. 104, 16th Division, 21st Special Base Force, 22nd Special Base Force, 23rd Special Base Force, 24th Special Base Force, 25th Special Base Force, C.M. Gunboat Ban'yō Maru, Okuyō Maru, Taikō Maru, 934th Naval Air Group |
| 5 February 1945 | Combined Fleet | 10th Area Fleet | 2nd Southern Expeditionary Fleet | Patrol boat No. 102, No. 106, No. 109, 21st Special Base Force, 22nd Special Base Force, 23rd Special Base Force, C.M. Gunboat Ban'yō Maru, 31st Naval Air Group |
| 3 September 1945 | Surrendered. | Surrendered. | Surrendered. | Surrendered. |
* Commander in chief
| | Rank | Name | Date | Note, additional post |
| 1 | Vice-Admiral | Ibō Takahashi | 10 April 1941 10 March 1942 | Commander in chief of the Southwest Area Fleet |
| 2 | Vice-Admiral | Shirō Takasu | 15 September 1942 | Commander in chief of the Southwest Area Fleet |
| 3 | Vice-Admiral | Seiichi Iwamura | 15 April 1943 | |
| 4 | Vice-Admiral | Gun'ichi Mikawa | 3 September 1943 | |
| 5 | Vice-Admiral | Shiro Kawase | 18 June 1944 | |
| 6 | Vice-Admiral | Yaichirō Shibata | 29 January 1945 | |
* Chief of staff
| | Rank | Name | Date | Note, additional post |
| 1 | Rear-Admiral | Toshihisa Nakamura | 10 April 1941 10 March 1942 | Chief of staff of the Southwest Area Fleet |
| 2 | Rear-Admiral | Takeo Tada | 10 April 1942 | Chief of staff of the Southwest Area Fleet |
| 3 | Captain Rear-Admiral | Akira Matsuzaki | 15 April 1943 1 May 1943 | |
| 4 | Rear-Admiral | Shinzaburō Hase | 19 January 1945 | |

### 3rd Southern Expeditionary Fleet

The 3rd Southern Expeditionary Fleet (第三南遣艦隊, Dai-San Nanken Kantai) was organized on 3 January 1942 for invasion of the Philippines.
* Structure (extract)
| Date | Highest unit | Higher unit | Lower units, vessels and elements |
| 3 January 1942 (original) | Combined Fleet | | Cruiser Kuma, Minelayer Yaeyama, 1st Escort Division, 31st Special Base Force, 32nd Special Base Force, C.M. Seaplane tender Sanuki Maru, C.M. Minelayer Nichiyū Maru, C.M. Survey ship Kyōodō Maru No. 36 |
| 14 July 1942 | Combined Fleet | Southwest Area Fleet | Cruiser Kuma, 31st Special Base Force, 32nd Special Base Force, C.M. Seaplane tender Sanuki Maru, C.M. Minelayer Nichiyū Maru, C.M. Survey ship Kyōodō Maru No. 36, 31st Naval Air Group, 2nd Surveying Unit |
| 1 September 1943 | Combined Fleet | Southwest Area Fleet | Minelayer Yaeyama, Gunboat Karatsu, 32nd Special Base Force, 954th Naval Air Group, 31st Guard Unit, 31st Communication Unit |
| 15 August 1944 | Combined Fleet | Southwest Area Fleet | Minelayer Tsugaru, Gunboat Karatsu, Torpedo boat Hayabusa, Patrol boat No. 103, No. 105, Submarine chaser No. 36, No. 45, No. 46, C.M. Gunboat Kiso Maru, 30th Special Base Force, 32nd Special Base Force, 33rd Special Base Force, 31st Naval Air Group, 32nd Naval Air Group, 31st Guard Unit, 31st Communication Unit |
| 1 June 1945 | Supreme Headquarter of the Navy | Southwest Area Fleet | 30th Special Base Force, 31st Special Base Force, 32nd Special Base Force, 33rd Special Base Force, 21st Submarine chaser Division, 955th Naval Air Group |
| 3 September 1945 | Surrendered. | Surrendered. | Surrendered. |
* Commander in chief
| | Rank | Name | Date | Note, additional post |
| 1 | Vice-Admiral | Rokuzō Sugiyama | 3 January 1942 | |
| 2 | Vice-Admiral | Taiji Ōta | 1 December 1942 | |
| 3 | Vice-Admiral | Arata Oka | 20 September 1943 | |
| 4 | Vice-Admiral | Gun'ichi Mikawa | 15 August 1944 | Commander in chief of the Southweat Area Fleet and 13th Air Fleet |
| 5 | Vice-Admiral | Denshichi Ōkawachi | 1 November 1944 8 January 1945 | Commander in chief of the Southweat Area Fleet and 13th Air Fleet Commander in chief of the Southweat Area Fleet |
* Chief of staff
| | Rank | Name | Date | Note, additional post |
| 1 | Rear-Admiral | Yasuichirō Kondō | 3 January 1942 | |
| 2 | Captain Rear-Admiral | Shōzō Hashimoto | 11 August 1943 1 May 1943 | |
| 3 | Rear-Admiral | Hisagorō Shimamoto | 27 July 1944 | |
| 4 | Rear-Admiral | Kaoru Arima | 1 November 1944 17 November 1944 5 February 1945 | Chief of staff of the Southwest Area Fleet, 13th Air Fleet and commander of the 32nd Special Base Force Chief of staff of the Southwest Area Fleet and 13th Air Fleet Chief of staff of the Southwest Area Fleet |

### 4th Southern Expeditionary Fleet

The 4th Southern Expeditionary Fleet (第四南遣艦隊, Dai-Yon Nanken Kantai) was independent from 2nd Southern Expeditionary Fleet for maintenance of the public order in western New Guinea on 30 November 1943. Dissolved on 10 March 1945, their remaining units were unified to 10th Area Fleet.
* Structure (extract)
| Date | Highest unit | Higher unit | Lower units, vessels and elements |
| 30 November 1943 (original) | Combined Fleet | Southwest Area Fleet | Minelayer Itsukushima, 24th Special Base Force, 25th Special Base Force, 26th Special Base Force, 934th Naval Air Group |
| 1 March 1945 | Combined Fleet | Southwest Area Fleet | 25th Special Base Force, 26th Special Base Force, 28th Special Base Force |
| 10 March 1945 | Dissolved. | Dissolved. | Dissolved. |
* Commander in chief
| | Rank | Name | Date | Note, additional post |
| 1 | Vice-Admiral | Seigō Yamagata | 30 November 1943 | |
* Chief of staff
| | Rank | Name | Date | Note, additional post |
| 1 | Rear-Admiral | Tametsugu Okada | 30 November 1943 | |