Caroline Islands

Alliance Axis - Minor Member Nation or Possession
Possessing Power Japan


ww2dbaseThe Caroline Islands in the South Pacific were named by explorer Francisco Lazcano for King Charles II of Spain in 1686. In 1875, Spain claimed these islands, and in 1899 the islands were sold to Germany. In 1914, Japanese troops occupied the islands during WW1, and after the war Japan received a League of Nations mandate over them. Between 1914 and 1933, restricted by the League of Nations, Japan was not able to build up the Caroline Islands for military purposes, but its departure from the League in Mar 1933 gave her the freedom to do so. The atoll of Truk was built as a forward naval base prior to the Pacific War; it hosted five airfields, several seaplane and torpedo boat bases, repair facilities, and during the war a radar station was constructed. Ulithi Atoll housed a weather station and was briefly used by the Japanese as an anchorage, although this did not last long as Truk had already taken this role. The island of Yap had a history as a German naval base prior to WW1, and it remained an important military base in Japanese possession. Ponape, now Pohnpei, also served as a major base.

ww2dbaseDuring WW2, the Truk base was destroyed in Feb 1944 by American airpower and was cut off for the remainder of the war. Ulithi Atoll was taken by the Americans in Sep 1944 unopposed, and it became the an American forward naval base even larger than Pearl Harbor in Hawaii; the Japanese attempted to attack the base several times, but the effects were only marginal. Yap was bypassed by the Americans, blockaded with the garrison of about 5,000 men left to starve. Ponape, with a garrison of about 8,000 men was likely skipped over.

ww2dbaseAfter the war, the Caroline Islands became parts of the Trust Territory of the Pacific Islands administered by the United States. In 1986, the new nation of the Federated States of Micronesia was formed, and it gained sovereignty over the Caroline Islands.

ww2dbaseSource: Wikipedia

Last Major Update: Apr 2012

Events Taken Place in Caroline Islands
Attack on Truk16 Feb 1944 - 18 Feb 1944
Palau Islands and Ulithi Islands Campaigns15 Sep 1944 - 1 Dec 1944


Japanese heavy cruiser Chokai at Truk, Caroline Islands, 20 Nov 1942; note battleship Yamato in backgroundYamato resting at anchor in Truk, Caroline Islands, 1943Battleships Musashi (foreground) and Yamato (background) at Truk, Caroline Islands, May 1943B-24J Liberator “Kansas Cyclone” of the 26th Bomb Squadron approaching targets in and around the Truk Lagoon, Caroline Islands, 1944. Note Udot Island below.
See all 128 photographs of Caroline Islands in World War II


Map of Ulithi Atoll, Caroline IslandsMap of the Palau Islands, 1944US Navy 1944 berthing chart for the Northern Anchorage of the Ulithi Lagoon, Caroline IslandsUS Navy Mooring Plan for Ulithi Lagoon, Caroline Islands, Jun 1945. Ships’ logs suggest there was an as yet unknown earlier mooring plan for Ulithi but this one was in use at least from Nov 1944.

Caroline Islands in World War II Interactive Map

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Visitor Submitted Comments

1. Anonymous says:
17 Apr 2015 10:48:22 PM

To whom it may concern:

Thank you for this informative article about the Caroline Islands. Regarding the statement that the name “Ponape” is “now anglicized as Pohnpei,” that is incorrect. “Ponape” is a spelling that reflects an older form of the indigenous pronunciation of the island. Today, the Pohnpeian government has adopted an official orthographic system. As such, the spelling “Pohnpei” is the indigenous spelling. It is not an anglicization of “Pohnpei.” If anything, it is an updated indigenous spelling.

many thanks,

Emerson Odango, PhD
University of Hawai‘i at Mānoa
2. Commenter identity confirmed C. Peter Chen says:
18 Apr 2015 07:03:56 AM

Thank you Emerson, the correction has been made.

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Caroline Islands in World War II Photo Gallery
Japanese heavy cruiser Chokai at Truk, Caroline Islands, 20 Nov 1942; note battleship Yamato in background
See all 128 photographs of Caroline Islands in World War II

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