15 November 1939: Australian, British and French warships began patrolling the Indian Ocean when the Germanpocket battleshipAdmiral Graf Spee sank the tankerAfrica Shell south ofMadagascar.[1]
23 March 1940: The Royal Navy established the Malaya Force of cruisers,destroyers andsubmarines to stop German merchant ships leaving the Dutch East Indies.[2]
11 May 1940: German merchant raiderAtlantis entered the Indian Ocean from the South Atlantic.[3]
7 June 1940: Italian warships began minelaying off Massawa andAssab.[4]
10 June 1940: Eight Italian submarines began war patrols of the Indian Ocean from Massawa.[5] Some of these submarines were lost because leakage ofchloromethaneair conditioning refrigerants causedcentral nervous system poisoning of their crews from recirculating air during submerged operations.[6]
10 June 1940:Atlantis captured the freighterTirranna in the Central Indian Ocean.[3]
16 June 1940: Italian submarineGalileo Galilei sank the tankerJames Stove.[5]
19 June 1940:Galileo Galilei was captured by the Britishnaval trawlerMoonstone.[5]
23 June 1940: Italian submarineTorricelli sankHMS Khartoum before being sunk by accompanying destroyers.[5]
24 June 1940: Italian submarineGalvani sank the sloop HMISPathan before being sunk by the sloopHMS Falmouth.[5]
11 July 1940:Atlantis sank the freighterCity of Bagdad south of India.[3]
13 July 1940:Atlantis sank the freighterKemmendine south of India.[3]
2 August 1940:Atlantis sank the freighterTallyrand in the central Indian Ocean.[3]
17 August 1940: Royal Navy and Royal Australian Navy cruisers and destroyers covered the withdrawal of British troops fromBritish Somaliland toAden.[7]
24 August 1940:Atlantis sank the freighterKing City in the Central Indian Ocean.[3]
26 August 1940: German merchant raiderPinguin sank the tankerFilefjell south ofMadagascar.[8]
27 August 1940:Pinguin sank the tankerBritish Commander and the freighterMorviken south of Madagascar.[8]
6 September 1940: Italian submarineGuglielmotti sank the tankerAtlas in the Red Sea.[9]
9 September 1940:Atlantis sank the tankerAthelking in the central Indian Ocean.[3]
10 September 1940:Atlantis sank the freighterBenarty in the central Indian Ocean.[3]
12 September 1940:Pinguin sank the freighterBenavon east of Madagascar.[8]
16 September 1940:Pinguin captured the freighterNordvard in the central Indian Ocean.[8]
Early focus wasAllied neutralisation and capture ofRegia Marina African naval bases, followed by invasions ofIraq in April andIran in August, to displace governments friendly to theAxis powers. Later Allied focus was on destruction ofKriegsmarine commerce raiders and moving troops to defend against anticipated Japanese expansion into south-east Asia.
1 March 1941: Five Fairey Albacore from HMSFormidable raided Massawa.[14]
3 March 1941:Admiral Scheer returned to the South Atlantic to evade Allied warships.[14]
4 March 1941: The four surviving Italian submarines abandoned the Massawa base and escaped into the South Atlantic.[15] The German supply shipCoburg and prizeKetty Brövig were scuttled when stopped byHMAS Canberra and HMNZSLeander, north of Madagascar.[14]
16 March 1941: Invasion ofBerbera by Royal Navy Force D.[16]
1 April 1941: The German SSBertrand Rickmers was scuttled when stopped by HMSKandahar.[16]
8 April 1941: Six Italian destroyers and 17 Axis merchant ships were sunk or scuttled when Allied troops captured Massawa.[17]Atlantis left the Indian Ocean via the South Atlantic.[18]
30 January 1942:I-64 sank the freightersFlorence Luckenbach,[33]Jalapalaka andJalatarang in theBay of Bengal.[30]
15 February 1942:I-65 sank the freighterJohanne Justesen off Ceylon.[30]
16 February 1942: An Allied troop convoy from Darwin to Timor was turned back by Japanese air attack.[34]
19 February 1942: Japanese invasion ofBali.Bombing of Darwin by theKido Butai sankUSS Peary, the tankerBritish Motorist, the freighterMauna Loa, and linersNeptuna andZealandia.[34]
20 February 1942: Japanese invasion of Timor.[34]I-65 sank the freighterBhima in theArabian Sea.[30]
28 February 1942:Japanese submarine I-53 sank the freighterCity of Manchester west of Sumatra,[36] andI-4 sank the freighterBan Ho Guan south of Java.[30]
1 March 1942: Japanese battleshipsHiei andKirishima sank USSEdsall,USS Pecos and the freighterTomohon, and Japanese cruiserAshigara sankUSS Pillsbury south of Java.[37] Japanese submarineI-2 sank the freighterParigi,I-59 sank the linerRooseboom west of Sumatra, andJapanese submarine I-54 sank the freighterModjekerto south of Java.[30]
2 March 1942: Japanese warships sank the freighterProminent off Tjilatjap, andHayashio captured the freighterSigli.[30]
3 March 1942: Japanese warships sankUSS Asheville south of Java,[37] Japanese submarineI-1 sank the freighterSiantar off Tjilatjap, and Japanese aircraft sank the linerKoolama in theTimor Sea.[30]
4 March 1942: Japanese warships sankHMS Stronghold,HMAS Yarra and the tankerFrancol south of Java.[37] Japanese submarineI-62 sank the freighterMerkus off Tjilatjap, andI-7 sank the linerLe Maire.[30]
5 March 1942:Kido Butai aircraft sank the freightersManipi,Tohiti,Rokan,Kidoel,Poelau Bras andDayak raiding Tjilatjap.Poelau Bras lifeboats attacked.[38]
7 March 1942: Allied naval forces covered the withdrawal of Allied troops from Rangoon.[39] Japanese battleshipsKongo andHaruna sank the freighterWoolgar while shelling Christmas Island.[40]
8 March 1942: Japanese troops captured Rangoon.[39]
6 April 1942: Japanese cruisers sank the linerDardanus and freightersSilksworth,Autolycus,Malda,Shinkuang,Gandara,Indora,Bienville,Selma City,Ganges,Banjoewangi,Batavia,Taksang,Sinkiang,Exmoor andVan der Capellen in the Bay of Bengal during Operation C. Japanese submarineI-5 sank the freighterWashingtonian.[48] Japanese aircraft sankHMIS Indus offSittwe.[49]
13 November 1942:U-178 sank the freighterLouise Moller,[58] andU-181 sank the freighterExcello east of South Africa.[62]
19 November 1942:U-177 sank the freighterScottish Chief, andU-181 sank the freighterGunda east of South Africa.[58]
20 November 1942:U-177 sank the Liberty shipPierce Butler,[63] andU-181 sank the freighterCorinthiakos east of South Africa.[58]
21 November 1942:U-181 sank the freighterAlcoa Pathfinder east of South Africa.[63]
24 November 1942:U-181 sank the freightersMount Helmos andDorington Court east of South Africa.[58]
26 November 1942: German blockade runnerRamses scuttled when stopped by escorts of convoy OW 1.[64]
27 November 1942:U-178 sank the Liberty shipJeremiah Wadsworth south of South Africa.[58]
28 November 1942:U-177 sank the troopshipNova Scotia drowning 750, andU-181 sank the freighterEvanthia east of South Africa.[58]
30 November 1942: German commerce raiderMichel sank the freighterSawokla,[65]U-177 sank the troopshipLlandaff Castle east of South Africa, andU-181 sank the freighterCleanthis in theMozambique Channel.[58]
1 December 1942:HMAS Armidale was sunk by Japanese aircraft while evacuating personnel from Timor.[64]
2 December 1942:U-181 sank the freighterAmarylis east of South Africa.[58]
7 December 1942:Michel sank the freighterEugenie Livonos east of South Africa,[65] andU-177 sank the freighterSaronikos in the Mozambique Channel.[58]
12 December 1942:U-177 sank the freighterRFA Empire Gull east of South Africa.[58]
14 December 1942:U-177 sank the freighterSawahloento east of South Africa.[58]
Axis submarine patrols of Indian Ocean trade routes were expanded with establishment of aKriegsmarine base inPenang asAllied anti-submarine patrols became increasingly effective in the Atlantic. Allied submarines and aircraft began patrolling theStrait of Malacca andAndaman Sea to intercept shipping supporting Japanese forces inBurma.
11 February 1943:U-516 sank the freighterHelmsprey east of South Africa.[68]
17 February 1943:U-182 sank the freighterLlanashe andU-516 sank the freighterDeer Lodge east of South Africa.[68]
18 February 1943: Convoy Prophet returned 30,000 soldiers of theAustralian 9th Division from Africa to Australia.[69]
26 February 1943:Kyo Maru No. 3 was mined offRangoon.[70]
27 February 1943: Tenth Air Force B-24s sankAsakasan Maru in the Andaman Sea.[70]U-516 sank the Dutchsubmarine tenderColumbia east of South Africa.[68]
3 March 1943:U-160 sank theLiberty shipHarvey W. Scott[71] and the freighterNipura east of South Africa.[68]
4 March 1943:U-160 sank the freightersMarietta andEmpire Mahseer east of South Africa.[68]
7 March 1943:U-506 sank the freighterSabor east of South Africa.[68]
8 March 1943:U-160 sank the Liberty shipJames B. Stephens east of South Africa.[72]
9 March 1943: Interned German freightersDrachenfels,Ehrenfels andBraunfels were scuttled atGoa.[73]U-506 sank the Norwegian freighterTabor south of South Africa.[68]
11 March 1943:U-160 sank the freighterAelbryn,[68] andU-182 sank theLiberty shipRichard D. Spaight east of South Africa.[74]
Use ofUltra intelligence information increased successful interceptions byAllied submarines and reducedAxis resupply opportunities in the Indian Ocean. Surrender of theRegia Marina and destruction ofKriegsmarinebattleships made Royal Navy aircraft carriers available for raids of theAndaman Sea.
25 January 1944:U-188 sank the freighterFort la Maune in the Arabian Sea.[94]
26 January 1944:U-532 sank the Liberty shipWalter Camp in the Arabian Sea.[96]U-188 sank the linerSurada and the freighterSamouri in the Arabian Sea.[94]
29 January 1944:U-188 sank the freighterOlga E. Embiricos in the Arabian Sea.[94]
3 February 1944:U-188 sank the Liberty shipChung Cheng in the Arabian Sea.[94]
9 February 1944:U-188 sank the freighterViva in the Arabian Sea.[94]
13 March 1944: The U-boat refuelling oilerBrake scuttled when found by aircraft fromHMS Battler acting on Ultra.[94]Japanese submarine I-26 sank the tankerH.D. Collier.[101]
19 March 1944:U-510 sank the Liberty shipJohn A. Poor in the Arabian Sea.[102]
17 October 1944:Operation Millet raid against Port Blair by HMSIndomitable andVictorious.[121]
2 November 1944:HMS Shalimar shelled Port Blair.[122]U-181 sank the tankerFort Lee in the central Indian Ocean. Allied aircraft sankTatayama Maru in the Andaman Sea.[123]
18 November 1944:Operation Outflank air raid against northern Sumatra by HMSIndomitable andIllustrious.[124]
22 November 1944:HMS Stratagem was sunk by Japanese destroyers in the Strait of Malacca.[122]
Allied focus was on amphibious operations along theBurma coast of theAndaman Sea.Axis submarine operations were restricted by fuel shortage and maintenance difficulties.
3 January 1945: Operation Lightning Allied invasion ofAkyab.[127]