On May 6, 1942 departs Singapore escorted by Hatakaze arriving to Yokosuka nine days later. On August 9, 1942 transits Bungo Straits and again on September 28, 1942

On November 3, 1942 Irako is escorted by Nasami off Fukajima southward 32°  North Latitude before departing and Irako proceeded to Truk. On November 9, at 10°  North Latitude escorted by Asanagi to Truk arriving the next day.

On November 24, 1942 departs Truk escorted by Oite, the next day proceeds alone towards Japan. On November 30, escorted by Nasami through the Bungo Straits to Fukajima. On December 13, 1942 escorted by Nuwajima off Mizunoko lighthouse until reaching Toi Misaki the next day.

During 1943, Irako makes twelve round trips from Japan to Truk.

On January 12, 1943 departs Truk traveling via Bungo Straits with Zuikaku, Suzuya, Ariake, Yugure and Amagiri and Jingei. On January 23, 1943 joined by torpedo boat Hato and CH-39 off Mizunoko Lighthouse, with CH-39 detached the next day before arriving at Truk. On February 2, 1943 provisions Sanyo Maru and seven days later again provisions the same vessel then departs for Japan.

Afterwards, departs Truk and on March 5, 1943 escorted by torpedo boat Hato south through the Bungo Straits

5 March 1943:
Joined by torpedo boat HATO off Fukajima and escorted south through the Bungo Straits.
E

6 March 1943:
HATO is detached 90 degrees off Toi Misaki.

10 March 1943:
At 13-50N 142-25E IRAKO meets up with destroyer OITE that escorts the ship south-east.

13 March 1943:
Arrives at Truk.

15 March 1943:
Captain Okano Keizaburo assumes command.

30 March 1943:
Joined by patrol boat PB- 46 at 29-05N, 134-04E and escorted north through the Bungo Straits.
E

31 March 1943:
PB-46 is detached off Fukajima.

14 April 1943:
Joined by minelayer Yurijima off Fukajima and escorted south through the Bungo Straits.
E

15 April 1943:
Yurijima is detached 90 degrees off Toi Misaki.

28 April 1943:
Departs Truk for Iwo Jima escorted by destroyer TANIKAZE.

1 May 1943:
Arrives at Iwo Jima.

4 May 1943:
Joined by subchaser CH-35 at 30-40N, 133-40E.
E

5 May 1943:
CH-35 is detached off Fukajima.

24 May 1943:
Departs Kure for Truk with armed merchant cruiser AIKOKU MARU. At sea, joins a convoy from Yokosuka consisting of escort carriers UNYO and CHUYO escorted by Umikaze.

29 May 1943:
Arrives at Truk.

28 June 1943:
At 1730, IRAKO departs Yokosuka in convoy No. 3628 consisting of HAKUSAN MARU escorted by destroyer Ikazuchi.

6 July 1943:
Arrives at Truk.

25 July 1943:
IRAKO departs Truk for Kure with cruiser AOBA in an unidentified convoy escorted by destroyers Amatsukaze and URAKAZE.

1 August 1943:
IRAKO enters the Bungo Straits with AOBA, Amatsukaze and URAKAZE. Later that day, arrives at Kure.

12 September 1943:
Departs Truk escorted by minelayer TSUGARU and destroyer HAMAKAZE.

18 September 1943:
Arrives at Yokosuka.

19 September 1943:
Captain Miyamoto Yasozo (40)(former CO of NOJIMA) is appointed CO.

4 October 1943:
IRAKO departs Yokosuka in convoy No. 3002 consisting of TOKYO MARU escorted by destroyer SHIRATSUYU.

12 October 1943:
Arrives at Truk at 0500.

14 November 1943:
At 1400, IRAKO, departs Yokosuka in fleet convoy No. 3115 with transport (ex-sub tender) HEIAN MARU and aircraft transport KEIYO MARU escorted by destroyer YUKIKAZE and kaibokan OKI.

16 November 1943:
Lookouts on HEIAN MARU sight an enemy submarine travelling in the opposite direction. (probably USS DACE (SS-247).

19 November 1943:
LAt 0724 (JST), tCdr (later Captain/victor of SHINANO) Joseph Enright's (USNA ’33) USS DACE (SS-247), on her first patrol, attacks the convoy unsuccessfully. Enright targets HEIAN MARU. A torpedo barely misses the bow of OKI. The kaibokan counter-attacks with depth-charges. Even HEIAN MARU drops a DC, but the USS DACE escapes undamaged.

23 November 1943:
At 1550, arrives at Truk.

5 December 1943:
Departs Truk in convoy No. No. 4205A with submarine tender YASUKUNI MARU escorted by kaibokan MIKURA.

7 December 1943:
Kaibokan HIRADO joins the escort of convoy No. 4205A.

10 December 1943:
The convoy arrives at Saipan.

14 December 1943:
Arrives at Yokosuka.

On January 4, 1944 departed Yokosuka escorted by Shigure and Harusame bound for Truk arriving seven days later. On January 13, 1944 at Truk, provisions Heian Maru and again provisions her three days later.

On January 20, 1944 departs Truk escorted by Satsuki, Akebono and Ushio. At roughly 8' 4" N, 152 40" E hit by a torpedo fired by USS Seadragon (SS-194) northwest of Truk. Hit in the starboard bow that causes medium damage and flooding in the bow and leaves the vessel adrift off the North Passage. Suzukaze departs Truk to assist.

On January 21, 1944 Chokai tows Irako back to Truk escorted by Suzukaze and Ushio, arriving at 5:00pm. Undergoes temporary repairs, likely by Akashi until early Febraruy 1944

On February 13, 1944 departs Truk as part of convoy 4213 including Notoro, Tatsuura and Hibi Maru escorted by Manju, Oki and CH-31 arriving at Yokosuka on February 27, 1944.

On March 3, 1944 Irako undergoes repairs at Yokosuka and then is transfered to Mitsubishi Heavy Industries at Yokohama and Sasebo Arsenal for additional repairs until August 1944.

On July 5, 1944 assigned to the Southwest Area Fleet at Manila.

On August 10, 1944 departs Imari Bay as part of convoy HI-71 bound for Singapore. The convoy includes oilers AZUSA, KYOKUTO, TEIYO, EIYO, ZUIHO, AMATSU and NIYO MARUs, HAKKO MARU No. 2, fleet oiler HAYASUI, transports TEIA (ex-French ARAMIS), AWA, NOTO, HOKKAI and Noshiro Maru, IJA landing craft depot ships TAMATSU and MAYASAN MARUs and cargo ships KASHII, NISSHO and ORYOKU MARUs escorted by destroyers FUJINAMI and Yūnagi, kaibokan HIRADO, KURAHASHI, MIKURA, SHONAN, CD-11 and escort carrier TAIYO. The 631st NAG provides air cover with 12 BN5 “Kates”.

12 August 1944:
Off Nansei Shoto. IRAKO collides with TEIA MARU (ex-French liner ARAMIS), but the damage is minor.

15 August 1944:
HI-71 arrives at Mako, Pescadores. IRAKO and NIYO, HAKKO and ORYOKU MARUs are detached.

25 August 1944:
At 0630, IRAKO departs Moji in convoy HI-73 consisting of IJA landing craft depot ship KIBITSU MARU, armed merchant cruiser GOKOKU MARU, transports (ex-seaplane tenders) SANUKI and KAGU MARUs, tankers TOHO, OMUROSAN, OTOWASAN, TAIHO, FUJISAN, HAKKO, AMATO, TOA and KUROSHIO MARUs escorted by escort carrier UNYO, light cruiser KASHII and kaibokan CHIBURI, CD-13, CD-19, CD-21 and CD-27. Later that day, the convoy is joined briefly by transports MIZUHO, ARABIA and KOKURYU MARUs and tanker MANEI MARU.

26 August 1944:
At 0900, MIZUHO, ARABIA and KOKURYU MARUs are ordered away because of excessive smoke. MANEI MARU remains at Kyushu because of engine problems.'

On August 29, 1944 arrives at Takao Harbor and departs the same day and arrives at Tsoying on Formosa.

On August 30, 1944 off Saei on Formosa, the convoy splits with KIBITSU Maru, GOKOKU Maru, KAGU Maru and Irako proceed to Manila Bay while the rest of the convoy proceeds to Singapore.

On September 21, 1944 U.S. Navy (USN) carrier aircraft attack Manila Bay. Anchored near Irako, Satsuki was sunk.

On September 22, 1944 at 3:00am departs Manila Bay carrying a load of reconnaissance floatplanes as part of a Taihi (refugee) convoy bound for Coron Bay along with CHINZEI, BAIKAL, Taiei Maru, TENHI, TAITEN, Olympia Maru, EKKAI and KOGYO MARUs escorted by minelayer Aotaka, auxiliary subchasers SHONAN MARU No. 11 and HAKKO MARU, CHa-60 and CHa-61. Arriving at Coron Bay. Irako anchors between Tangat Island and Lusong Island.

Sinking History
On September 24, 1944 while Irako was anchored in Coron Bay. Attacked by U.S. Navy (USN) carrier aircraft. the first wave scores direct bomb hits on the midship section of Irako, setting her bridge and superstructure on fire and begins sinking bow first, but is instead beached. Later, Irako sinks at 11°  58' N, 120° 2' E near the mouth of Coron Bay. Captain Miyamoto survives the sinking.

Also sunk were Taiei Maru, Olympia Maru, Ekkai Maru and Kogyo Maru. Officially, Irako was removed from the Navy list on November 30, 1945.

Shipwreck
Irako is considered the best shipwreck dive in the Philippines. The shipwreck is on a 43 meter bottom with the deck between 28-35 meters. The Irako is largely intact with good visibility. Big groupers, schools of tuna and yellow fin, lion fish and scorpion fish live around this wreck. Sea turtles live in the crumpled and folded metal of the superstructure. Deep penetration is possible through the engine room for experienced and properly equipped divers.

References
Combined Fleet - IJN IRAKO: Tabular Record of Movement

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Last Updated
November 17, 2023