Pacific War Timeline

(December 7, 1941 – September 2, 1945)

The Pacific War was the theater of World War II fought between the Allied powers—primarily the United States—and the Empire of Japan across the Pacific Ocean and East Asia. It began with Japan's attack on Pearl Harbor in December 1941 and ended with Japan's surrender in August 1945 following the atomic bombings of Hiroshima and Nagasaki. The conflict involved massive naval battles, island-hopping campaigns, and immense casualties on all sides. More Less

Go to: Timeline | Event List | Key Facts | Directory

Japanese Expansion

Second Sino-Japanese War begins

Jul 7, 1937 - Sep 9, 1945

The Second Sino-Japanese War began with the Marco Polo Bridge Incident, when Japanese and Chinese forces clashed near Beijing. Japan launched a full-scale invasion of China, capturing major cities including Shanghai, Nanjing, and Wuhan. The conflict became a central front of the Pacific War, causing enormous casualties among Chinese soldiers and civilians.

Image source: Second Sino-Japanese War

Battle of Nanjing

Dec 1, 1937 - Dec 13, 1937

Japanese forces captured Nanjing, then the capital of the Republic of China, after intense fighting. The fall of the city was followed by the Nanjing Massacre, in which Japanese troops committed widespread atrocities against Chinese civilians and disarmed soldiers over several weeks.

Image source: Battle of Nanking

Battle of Khalkhin Gol

May 11, 1939 - Sep 16, 1939

Soviet forces under Georgy Zhukov decisively defeated Japanese troops along the Mongolian-Manchurian border. The defeat discouraged Japan from attacking the Soviet Union and contributed to its decision to strike southward instead, shaping the strategic direction of the Pacific War.

Image source: Battles of Khalkhin Gol

Japan occupies French Indochina

Sep 22, 1940

Japanese forces entered northern French Indochina to secure bases and cut supply routes to China. The move provoked the United States to impose embargoes on scrap metal and later oil, escalating tensions that would lead directly to war in the Pacific.

Image source: Japanese invasion of French Indochina

Tripartite Pact signed by Axis powers

Sep 27, 1940

Germany, Italy, and Japan signed a mutual defense agreement in Berlin. The pact formalized the alliance between the European Axis powers and Japan, linking the conflicts in Europe and Asia into a single global struggle.

Image source: Tripartite Pact

Attack on Pearl Harbor

Dec 7, 1941

Japanese carrier aircraft launched a surprise strike on the United States Pacific Fleet at Pearl Harbor, Hawaii, sinking or damaging numerous battleships and killing over 2,400 Americans. The attack prompted the United States to declare war on Japan the next day, bringing America fully into World War II.

Image source: Attack on Pearl Harbor

Japanese invasion of Malaya

Dec 8, 1941 - Jan 31, 1942

Hours before or simultaneous with Pearl Harbor, Japanese forces landed on the Malay Peninsula and advanced rapidly down its length. Their superior tactics and air support overwhelmed British Commonwealth defenses, culminating in one of Britain's worst military defeats.

Image source: Malayan campaign

Fall of Hong Kong

Dec 8, 1941 - Dec 25, 1941

Japanese forces attacked the British colony of Hong Kong on the same day as Pearl Harbor. After eighteen days of fierce resistance by British, Canadian, Indian, and local troops, the garrison surrendered on Christmas Day, beginning a harsh Japanese occupation.

Image source: Battle of Hong Kong

Invasion of the Philippines begins

Dec 8, 1941 - May 6, 1942

Japan invaded the American-held Philippines within hours of Pearl Harbor. Despite determined resistance by Filipino and American forces under General Douglas MacArthur, the defenders retreated to Bataan and Corregidor, where they ultimately surrendered after months of siege.

Image source: Philippines campaign (1941–1942)

Sinking of HMS Prince of Wales and HMS Repulse

Dec 10, 1941

Japanese land-based aircraft sank two major British warships off the coast of Malaya. The disaster demonstrated the vulnerability of capital ships without air cover and crippled British naval power in the Far East at the outset of the Pacific War.

Image source: Sinking of Prince of Wales and Repulse

Battle of Wake Island

Dec 11, 1941 - Dec 23, 1941

The small American garrison on Wake Island repulsed an initial Japanese landing attempt but succumbed to a reinforced second assault. The island's capture gave Japan an important outpost in the Central Pacific.

Image source: Battle of Wake Island

Fall of Singapore

Feb 8, 1942 - Feb 15, 1942

Japanese forces crossed into Singapore island and overwhelmed its British-led defenders despite their numerical superiority. The surrender of approximately 80,000 Allied troops was described by Winston Churchill as the 'worst disaster' in British military history.

Image source: Fall of Singapore

Bombing of Darwin

Feb 19, 1942

Japanese carrier-based aircraft launched the largest attack ever mounted against Australia, striking the port of Darwin. The raid destroyed ships, aircraft, and infrastructure, bringing the war directly to Australian soil and heightening fears of invasion.

Image source: Bombing of Darwin

Bataan Death March

Apr 9, 1942

After the surrender of American and Filipino forces on Bataan, tens of thousands of prisoners were force-marched northward in brutal heat with little food or water. Thousands died from exhaustion, abuse, and executions, becoming one of the war's most notorious atrocities.

Allied Offensives

Doolittle Raid

Apr 18, 1942

Sixteen American B-25 bombers led by James Doolittle took off from the carrier USS Hornet to strike Tokyo and other Japanese cities. Though damage was modest, the daring raid boosted American morale and shocked Japanese leadership, contributing to their decision to attack Midway.

Image source: Doolittle Raid

Battle of the Coral Sea

May 4, 1942 - May 8, 1942

The first naval battle fought entirely between carrier aircraft, with opposing fleets never sighting each other. The Allies thwarted Japan's attempt to seize Port Moresby, halting a planned thrust toward Australia and costing Japan the services of two carriers for the coming battle at Midway.

Image source: Battle of the Coral Sea

Battle of Midway

Jun 4, 1942 - Jun 7, 1942

American codebreakers enabled US Navy carriers to ambush the Japanese fleet near Midway Atoll. In a decisive engagement, American dive bombers sank four Japanese fleet carriers while losing only one of their own, shifting the strategic balance of the Pacific War permanently in favor of the Allies.

Image source: Battle of Midway

Operation Cartwheel

Jun 30, 1943 - Aug 31, 1944

A major Allied strategy aimed at neutralizing the great Japanese base at Rabaul through a double envelopment by General MacArthur's Southwest Pacific forces and Admiral Halsey's South Pacific forces. Rather than assaulting Rabaul directly, the Allies bypassed and isolated it, exemplifying the island-hopping approach.

Image source: Operation Cartwheel

Battle of Tarawa

Nov 20, 1943 - Nov 23, 1943

US Marines stormed heavily fortified Betio Island in the Gilbert Islands against fanatical Japanese resistance. The bloody victory came at a high cost and taught American planners vital lessons about amphibious assaults that shaped subsequent island-hopping operations.

Image source: Battle of Tarawa

Leyte Gulf naval battle and Philippines liberation begins

Oct 20, 1944 - Oct 26, 1944

Following MacArthur's return to Philippine soil at Leyte, Japanese naval forces made their last major sortie, engaging in a series of massive sea battles. The Imperial Japanese Navy was shattered, and Japan first employed kamikaze suicide attacks on a large scale during this campaign.

Image source: Battle of Leyte Gulf

Major Battles

Kokoda Track campaign

Jul 21, 1942 - Nov 16, 1942

Australian troops fought a grueling series of battles along the Kokoda Trail in New Guinea's rugged jungle mountains, halting the Japanese advance toward Port Moresby. The campaign became legendary in Australia and marked a key check on Japan's southward expansion.

Image source: Kokoda Track campaign

Guadalcanal campaign begins

Aug 7, 1942 - Feb 9, 1943

US Marines landed on Guadalcanal in the Solomon Islands, initiating the first major Allied offensive against Japan. Six months of savage fighting on land, sea, and air ended with Japanese evacuation, giving the Allies a strategic foothold and momentum for future offensives.

Image source: Guadalcanal campaign

Battle of Savo Island

Aug 8, 1942 - Aug 9, 1942

A Japanese cruiser force surprised Allied naval units guarding the Guadalcanal landing area at night, sinking four heavy cruisers in one of the worst defeats in US Navy history. The loss left American ground troops temporarily unsupported and began months of naval duels around the island.

Image source: Battle of Savo Island

Battle of the Santa Cruz Islands

Oct 25, 1942 - Oct 27, 1942

Carrier forces of the United States and Japan clashed again near Guadalcanal. Tactically a Japanese victory that sank the USS Hornet, the battle cost Japan so many experienced aircrew that it could not sustain its carrier operations, a strategic blow it never recovered from.

Image source: Battle of the Santa Cruz Islands

Battle of Saipan

Jun 15, 1944 - Jul 9, 1944

American forces captured Saipan after weeks of ferocious combat marked by mass Japanese banzai charges and civilian suicides. The fall of Saipan placed Tokyo within range of new B-29 bombers and triggered the collapse of Japan's Tojo government.

Image source: Battle of Saipan

Marianas Turkey Shoot during Battle of the Philippine Sea

Jun 19, 1944 - Jun 20, 1944

In the largest carrier battle in history, overwhelming numbers of Japanese aircraft were shot down by American pilots and anti-aircraft fire, with losses so lopsided that American airmen called it the Great Marianas Turkey Shoot. Japan's naval aviation was effectively destroyed as a fighting force.

Image source: Battle of the Philippine Sea

Battle of Iwo Jima

Feb 19, 1945 - Mar 26, 1945

US Marines assaulted the volcanic island of Iwo Jima in one of the bloodiest battles of the war. Nearly all of the roughly 21,000 Japanese defenders died resisting from elaborate cave networks. The iconic flag-raising on Mount Suribachi symbolized the Marines' costly sacrifice.

Image source: Battle of Iwo Jima

Battle of Okinawa

Apr 1, 1945 - Jun 22, 1945

The last major amphibious campaign of the war saw American forces invade Okinawa, meeting desperate resistance and waves of kamikaze attacks. Massive casualties on both sides, along with enormous civilian deaths, foreshadowed the potential human cost of invading Japan itself.

Image source: Battle of Okinawa

End of the War

Atomic bombing of Hiroshima and Nagasaki

Aug 6, 1945 - Aug 9, 1945

The United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki three days apart. The unprecedented destruction, killing well over 100,000 people, shocked Japan's leadership and played a decisive role in the decision to surrender.

Image source: Atomic bombings of Hiroshima and Nagasaki

Soviet invasion of Manchuria

Aug 8, 1945 - Sep 2, 1945

The Soviet Union declared war on Japan and launched a massive offensive through Manchuria, swiftly overrunning Japanese Kwantung Army positions. The rapid Soviet success eliminated any hope Japan had of negotiating through Moscow and accelerated the move toward surrender.

Image source: Soviet invasion of Manchuria

Japan announces surrender

Aug 15, 1945

Emperor Hirohito announced Japan's acceptance of the Potsdam terms in a radio broadcast, the first time most Japanese had heard his voice. The announcement ended hostilities across the Pacific and Asia, though formal surrender documents were still to come.

Image source: Hirohito surrender broadcast

Formal surrender aboard USS Missouri

Sep 2, 1945

Japanese officials signed the Instrument of Surrender aboard the battleship USS Missouri in Tokyo Bay, formally ending World War II. The ceremony marked the close of the Pacific War and the beginning of the American occupation of Japan.

Image source: Surrender of Japan

Key Facts

The war began on December 7, 1941, when Japan launched a surprise attack on the U.S. naval base at Pearl Harbor, Hawaii, prompting the United States to enter World War II.
The Battle of Midway in June 1942 was a decisive turning point in which the U.S. Navy sank four Japanese aircraft carriers, shifting the strategic balance in the Pacific.
The Allies adopted an 'island-hopping' strategy, bypassing heavily fortified Japanese positions and capturing strategically important islands such as Guadalcanal, Iwo Jima, and Okinawa.
The war ended after the United States dropped atomic bombs on Hiroshima (August 6, 1945) and Nagasaki (August 9, 1945), leading to Japan's surrender on August 15, 1945, formally signed on September 2, 1945.
The Pacific War caused enormous casualties, with estimates of over 30 million deaths, including civilians in Japanese-occupied territories such as China, the Philippines, and Korea.

Source

This Pacific War timeline was generated with the help of AI, using information found on the internet.

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