In the early months of World War II, the United Stated spent several millions of dollars to fortify the West Coast against possible Japanese attack, going as far as to stretch a gigantic submarine net across the Juan de Fuca Strait and to cover the entire Boeing plant in Seattle with camouflaging wire net to make it look like a residential suburb.

Yet all these numerous fears of Japanese attack never materialized. Aside from sending a couple thousand bomb-filled balloons across the Pacific (all of which fell on sparsely inhabited areas), Japan never even touched the West Coast of America.

Why didn’t the Japanese attempt even a single attack on the mainland? What deterred them from striking such a direct blow on America? A submarine attack would have been easy for them, but they never sent a known submarine beyond the territorial waters of Hawaii.

So what’s the story here? Or were there attacks I simply didn’t come across in all my sources about World War II?

  • 19
    What would be the strategic objective of such an attack?
    – MCW
    Oct 31, 2016 at 14:42
  • 5
    "a couple thousand bomb-filled balloons across the Pacific (all of which fell on sparsely inhabited areas)" They didn't all fall on sparsely inhabited areas. One fell on Dundee, a suburb of Omaha. Oct 31, 2016 at 16:24
  • 4
    @georgestrieby I've been there and there's a brass plaque on a wall, of which I took a photograph. It seems the bomb actually exploded in the air over the town, so I'm not sure it was accurate of me to say it "fell on Dundee." Oct 31, 2016 at 17:48
  • 4
    Do you mean the early months of the USA's involvement in WWII?
    – OrangeDog
    Oct 31, 2016 at 17:51
  • 5
    Amateurs study tactics, professionals study logistics. Japan didn't launch any sort of large scale attacks against the continental US because we were too far away for them to support a major operation. Oct 31, 2016 at 18:26

11 Answers 11


There were several well-known attacks.

Aleutian Islands Campaign

On June 6, two days after the bombing of Dutch Harbor, 500 Japanese marines landed on Kiska, one of the Aleutian Islands of Alaska...The next day, a total of 1,140 Japanese infantrymen landed on Attu via Holtz Bay, eventually reaching Massacre Bay and Chichagof Harbor...The invasion was only the second time that American soil had been occupied by a foreign enemy, the first being the British during the War of 1812.

Submarine operations:

During 1941 and 1942, more than 10 Japanese submarines operated in the West Coast, Alaska, and Baja California. They attacked American, Canadian, and Mexican ships, successfully sinking over 10 vessels including the Soviet Navy submarine L-16 on October 11, 1942.

The United States mainland was first shelled by the Axis on February 23, 1942 when the Japanese submarine I-17 attacked the Ellwood Oil Field west of Goleta, near Santa Barbara, California.

In what became the only attack on a mainland American military installation during World War II, the Japanese submarine I-25, under the command of Tagami Meiji,[26] surfaced near the mouth of the Columbia River, Oregon on the night of June 21 and June 22, 1942, and fired shells toward Fort Stevens.

Balloon bomb attacks

Japan released about 9,000 bomb-carrying balloons across the Pacific between November 1944 and April 1945. Hundreds if not thousands of these actually landed in North America. The program was suspended after Allied bombing took out Japanese hydrogen plants. The Japanese didn't have much way of knowing how effective the bombs were, but one did cause casualties.

On May 5, 1945, five children and local pastor Archie Mitchell's pregnant wife Elsie were killed as they played with the large paper balloon they'd spotted during a Sunday outing in the woods near Bly, Oregon—the only enemy-inflicted casualties on the U.S. mainland in the whole of World War II.

It is somewhat incorrect to assume that there was no attempt by Japan to attack the mainland. There were attacks. However, Japan focused its military forces on the two main fronts, China and South-East Asia and it couldn't afford another front at the time.

  • 3
    I thought this was a very good answer, I edited to add another example just now.
    – Brian Z
    Oct 31, 2016 at 14:36
  • 8
    The I-25 did more than lob shells at the mainland, they also launched a sortie using seaplanes armed with incendiary missiles. "The two attacks on Oregon in September 1942 were the only World War II aircraft bombings on the continental United States." en.wikipedia.org/wiki/Nobuo_Fujita
    – Ivan
    Oct 31, 2016 at 17:56
  • 2
    There were indeed two incendiary bombing runs in Oregon near Brookings. (gesswhoto.com/oregon-bombing.html), (knowledgenuts.com/2014/09/06/…) Oct 31, 2016 at 22:04
  • Also, the lack of success has two interpretations. It could be that they were not all that interested in a major offensive, a likely thing, but also it could be that the defenses were sufficient to prevent large scale attacks.
    – BenPen
    Nov 2, 2016 at 20:05
  • and of course there were plans for years in Japan to bomb the Panama Canal, which was US territory at the time. Was never implemented because by the time the purpose built submarines to carry the aircraft were complete the war was over.
    – jwenting
    Dec 30, 2016 at 7:33

Japan had a lot of targets closer to home. They included Southeast Asia (which they conquered), China, and India (Japan came fairly close). They did attack American possessions on the far side of the Pacific such as Wake Island, Guam and the Philippines, plus Midway and the Aleutians, but otherwise, pretty much left mainland America alone after Pearl Harbor. Only when Japan had run out of Asian targets to attack, when the choice was between Australia, Iran, and San Francisco, would it make sense to attack the U.S. west coast. By that time, the Japanese planned to have a behemouth consisting of Japan, China, India, today's "ASEAN" nations, and maybe Siberian Russia behind her, but not before.

The Pacific was a relatively low priority theater for America, because it took America twice as many supplies to maintain one soldier against Japan in Asia versus Germany in Europe. Likewise, it would take a multiple more supplies for Japan to sustain an attack on the U.S. west coast versus say, China.

  • 2
    Yes. The background in some of the other answers is interesting, but sometimes the simplest answer is the most correct.
    – user18963
    Oct 31, 2016 at 20:08
  • 8
    Most Historians question why Japan did not try to cut off the Panama Canal as what most people forget about the USA in 1940 is there really wasn't anything on the West Coast of North America in 1940. Everything that was made beginning in World War 2 was made on the East Coast...and had to transit the Panama Canal to get to East Asia...so I don't think Japan took the US threat very seriously. The one major exception was of course Aircraft Production...which was a catastrophic failure of Axis Intelligence as no one saw the quantity, quality and devastating lethality of US Airpower "apriori... Nov 1, 2016 at 0:29
  • 1
    The attack on Dutch Harbor in Alaska was another "peculiarity" of the "War in the Pacific." Ironically this did elicit an powerful American response even though there really was nothing there...for either side actually. This Japanese "invasion" led directly to the building of the trans Canada highway through to Alaska overland...a very long way actually and one completely paid for by US taxpayers. This road is now a critical piece of economic infrastructure for North America...was a major achievement for "African Americans" actually as they pretty much built "the highway to nowhere." Nov 1, 2016 at 15:50
  • 5
    @user14394 "Most historians" don't question why Japan did not try to cut off the Panama Canal. A surface fleet would be vulnerable to attack in transit, the Canal had powerful gun batteries, and the Japanese navy couldn't spare the ships and logistics for the months it would take. But Japan did try to cut off the Panama Canal. They built huge aircraft-carrying submarines, the I-400 class, to attack the US. However they didn't have the industrial capacity to produce the planned 18 and only had 3 when the war ended.
    – Schwern
    Nov 1, 2016 at 22:30
  • 2
    @DrZ214 It's not just a little bit farther, it's twice as far. The Panama Canal is a 15,000 nmi round trip from Tokyo with no friendly ports to stop at for most of the journey. Their carriers did not have the range. They'd have to do a risky refuel at sea. At an economic 15 knots it would take 40 days with no radio contact. The defenses at Panana were prepared for air attack. LMK if you put that question up and I'll go into more detail.
    – Schwern
    Nov 5, 2016 at 6:18

Japanese submarines did come to the American Pacific coast. I know of one bombardment while visiting Fort Stevens on vacation. The attack did no damage, but appears to have helped foster fears of further attacks.

In the strategic sense, basically nothing happened on the American Pacific coast to change the course of the war, but one could argue that the defenses were a huge diversion of resources to guard against a threat that in hindsight was fairly marginal. However, had Japan won the Battle of Midway, then strong Pacific coast defenses would have been an even higher priority.

  • Without the defenses, the threat may not have been fairly marginal, Japan must have know about at least some of the defenses. Oct 31, 2016 at 17:54
  • I was disappointed when at Fort Stevens on learning it did not return fire. In fact the captain of the sub didn't know the fort was there and was trying to attract a destroyer to come out of harbor so he could torpedo it.
    – Joshua
    Oct 31, 2016 at 18:08
  • 2
    From nosing around Ft Stevens, I think it was perceived that the submarine shelling was a ruse to cause the fort to fire back, thereby disclosing their artillery positions and types. The guns were disappearing rifles that would raise and lower behind a gently sloping camouflaged parapet, so they could not be observed from the ocean side. The concrete emplacements are still there and you can walk around and in them.
    – Smith
    Nov 1, 2016 at 13:42
  • I've always thought that the "huge diversion of resources" was a cynical morale tactic, to remind people that we were actually in a war.
    – RonJohn
    Sep 22, 2017 at 2:03
  • @RonJon Actually, when you dig around West Coast fortifications you find they were built for many reasons that in hindsight seem extreme. The earliest forts at Ft Stevens were from the Civil War, yet it's hard to think that war of having anything happening in Oregon. A lot of the forts were significantly upgraded in/around the Pig War tensions with the UK. We all remember that conflict, right?
    – Smith
    Sep 23, 2017 at 15:21

Range of their ships...

The Japanese doctrine dictated a naval battle near the home islands, a repeat of the Russo-Japanese war. They did so largely because they lacked enough fuel to reliably reach, much less maintain any kind of battle fleet off the coast of the U.S.

The major reason that a Japanese carrier attack on Pearl Harbor was of low probability was that it was believed the Japanese lacked the ability to refuel underway, especially in the North Pacific in the winter. Such refueling was absolutely necessary because a battle fleet absolutely required the protection of its destroyers and destroyers were small fast ships that carried little fuel and quickly burned through that which they did.

The U.S. had only managed to accomplish underway refueling under simulated war conditions in late 1939 using a newly invented and highly secret disposable fast decoupler for the fuel lines. Knowing the Japanese lacked this technology, it was thought unlikely they could reach Hawaii.

But as usual, the Japanese used hyper-intensive training and much higher tolerance for casualties to build the skills necessary to perform such refueling. Most of those superbly trained men died at Midway trapped in the inferno the hangar decks of the stricken Japanese carriers turned into, after the American bomb strikes.

Fuel oil ruled the Pacific War in 1942. The U.S. stupidly let itself get by with only three fleet oilers (tankers who could keep pace with battle fleets which traveled at twice the speed of regular merchant ships and tankers). Two were sunk or damaged and the U.S. relied on civilian tankers to support all their operations. See: Black Shoe Carrier Admiral: Frank Jack Fletcher at Coral Sea, Midway & Guadalcanal.

Every one of the battleships sunk and then razed at Pearl Harbor were relegated to patrolling the West Coast because they did not have either the speed or range to keep pace with carrier task forces. Neither did the U.S. have enough tanker capacity to support them away from home ports.

The real question is why the Japanese did not utilize their submarines like the Germans. Had they deployed submarines along the West Coast as the Germans did during Operation Drumbeat, they could have devastated the U.S. pacific merchant fleet and crippled all offensive actions.

They didn't do so because they were fighting a scripted war. They knew they could not defeat the Americans materially in a long war, so they all deluded themselves that the war would be decided by a quick devastating destruction of the Pacific fleet in one massive decisive battle. At which point the Americans who where nothing but greedy, craven businessmen, would beg for peace.

They originally planned on luring the U.S. Fleet to a decisive battle somewhere between the Philippines and Okinawa. The sole doctrine for the Japanese subs was to whittle down the U.S. battle fleet as it traveled across the Pacific to the area of the decisive battle. Sub commanders were ordered to ignore merchant vessels and only attack warships.

Worse, the doctrine required large fleet subs, able to travel on the surface with the main battle fleet. This made the sub too large to dive quickly, so they suffered high losses when they ventured too far into areas where the U.S. had dense air patrols. Even if they had decided to deploy their ship in anti-logistics attacks on the west coast, they didn't have subs suitable for such a mission.

The Japanese inflexibility to the point of delusion, gave the U.S. a year to build a real logistics system and unlearn all the mistaken doctrines the Navy had developed after not having fought a serious naval war since 1898.

In the end, the Military, who thought of themselves as Samurai whose only role was war, were so desperate to maintain their role and status that they deluded themselves they could win a war with U.S. But they could only win a war that followed a specific narrow script. The script said that the war would end long before logistics issues came into play; they did not plan on attacking U.S. logistics nor did they rush to develop the Indonesian oil fields.

  • 1
    One detail: the battleships raised from Pearl Harbor were used extensively in the Western Pacific, mostly to bombard shore installations, but also in the battle of the Surigao Strait, the last battle between battleships in history.
    – sdenham
    Nov 5, 2016 at 15:56
  • I think you used the word "razed" where you meant "raised". Very different.
    – Joel
    Nov 6, 2016 at 13:44

Japan, like all major navies, had doctrines that were highly influenced by Mahon's book The Influence of Sea Power Upon History published in 1890, which emphasized the critical role of capital ships (battleships) in defensive roles in the home waters. The US Pacific Fleet was deployed forward, at Pearl Harbor, in an position to conduct offensive operations throughout the Pacific. Japan could not execute its strategic plan of dominating China and Indonesia with the US threatening its rear.

Ironically, the very success of the attack on Pearl Harbor rendered the battleship obsolete except as a floating artillery battery against land targets. A single pilot, flying an aircraft that could be quickly an cheaply produced, dropping an inexpensive bomb or torpedo could cripple or sink a very long leadtime, expensive battleship with thousands of crew.

Yamamoto immediately recognized the significance of his accomplishment at Pearl and set out an elaborate plan to draw the few US aircraft carriers into battle near Midway. Part of his plan was the diversion in the Aleutian Islands with the occupation of Siska, for domestic propaganda purposes, and an attack toward Dutch Harbor, which is the only deep water port on the Great Circle (i.e., shortest) route from Japan to the US. Thanks to breaking the Japanese naval code and a lot of skull sweat, Nimitz knew that would not be the main event. The battle of Midway, just months after Pearl, was a stunning defeat for the Japanese Navy, which lost 4 carriers in 5 minutes. After that, the US had the strategic initiative and rolled up the enemy outposts along the chain of islands leading east to New Guinea and then north to Okinawa and eventually the home islands.

From June 1942, Japan was on the strategic defense. There was little coastwise commerce along the West Coast to disrupt (mainly timber, which could be moved by rail, if necessary). There was a high probability of surface craft being detected and attacked by land based aircraft, and the flow of materiel from San Francisco, Seattle, Los Angeles and San Diego was convoyed and at the outer limits of submarine operations. Japan lacked a strategic air arm capable of inflicting substantial damages and casualties on American cities. There was no likelihood of inflicting sufficient damage to bring the US to negotiations.

In short, offensive operations against the US mainland were high-cost, low-payoff missions that detracted from the fierce rearguard retreat toward the home islands.


The following map - somewhat ironically - was recently granted the prestigious Grand Award of Japan for design. As you can see, the distance between Japan and the United States is quite large.

enter image description here

Another geographic feature that simply dealt a better hand to the Americans in WWII was island placement. Hawaii, being somewhat halfway in between the U.S. and Japan is pretty much your last stop till you hit California. That's a long supply chain to deal with, even if the Japanese decisively conquered Hawaii. And even then, if the Japanese successfully invaded the West Coast and took over major cities like San Francisco or Los Angeles, they would have to deal with the sprawling network of railways and automobiles which could bring Americans to the front lines much faster than a Japanese resupply coming in from Hawaii, much less Japan itself.

It is also worth noting that there is a decently spaced chain of islands and atolls that stretch from Hawaii to the Philippines and southern Japanese islands like Okinawa, which put Japan on the defensive for much of their fight against America. After the Japanese conquered America's Pacific outposts, it had to hold them at all costs to stave off what eventually became their inevitable defeat.

  • 2
    My understanding of this map is that it reduces distortions of landmasses. However flat projection of spheres must always compromise somewhere, and in this case areas of ocean are greatly distorted - e.g. the South Africa to Antarctica distance is not more than twice the South Africa to the Arctic distance. While I agree with you that (paraphrasing) "the Pacific is big", I don't think this projection is the best one to show that. Nov 1, 2016 at 20:28
  • 1
    Shanghai to San Francisco: 9873 km; San Francisco to New York: 4139 km. That correlates well with the map above. @DigitalTrauma: That is an absurd example, as it specifies objects on opposite sides of the map. There may well be areas of the map with significant distortion, but that is not one as is readily seen by rolling the opposite ends of the map together.. Nov 2, 2016 at 4:02
  • I'd like to upvote this. The Japaense were well aware of their manpower limitations. An invasion or sustained attack on the west coast was simply not realistic, and clearly ancillary to gaining resources and power in Asia. Of course, one could conjecture that had they been successful, they eventually would have turned to the American mainland. Indeed the entire point of the Pearl Harbor attack was to knock out the Navy and force the USA to sue to peace, allowing Japan to run amok in SE Asia and beyond
    – Hefewe1zen
    Jan 7, 2017 at 18:33

I've been in excavation for 30 years...all that to say...I love "Man and Machine" and I have paid close attention to some of the logistical side of man-made machines.

I believe the "hit and run" sub attacks created good psychological fear along with the balloon bombs. But to amass a fleet of ships to actually sail the distance to American coast lines would have been a suicide mission. They would be too far from "support" to carry out a continued attack and land invasion.

My understanding is, we, at the time had a very effective civil air patrol very willing to patrol our skies...and they did. This would have helped a great deal in spotting ships afar.

  • 3
    This answer would be improved with sources.
    – MCW
    Nov 1, 2016 at 14:39
  • 1
    Good answer. Google "pby Catalina" as US Airpower literally made itself felt on December 8th, 1941. There was no way Japan was going to attack or invade the West Coast of the USA in World War 2. The flip side turned out to be "now the United States is going to attack you" I might add. Once we discovered the Panama Canal was free and clear "the Eastern United States and Canada had Happy Time.... Nov 1, 2016 at 16:06
  • Logistics, +1. The Allies were led by a man who decided we needed nearly two hundred thousand deuce and a half's to win WWII (which were mainly used as non-combat vehicles). How's that for a source? ;)
    – Mazura
    Nov 2, 2016 at 8:20
  • Oops, looks like my numbers were a little off: "By the end of production in 1945, 562,750 CCKWs in all variants had been built, a total second only to the “Jeep”."
    – Mazura
    Nov 2, 2016 at 8:25

Another bombing of the Continental US by Japan that was not mentioned yet was the Japanese bombing of Oregon via submarine-launched bomber planes.

The Lookout Air Raids are bombings that were carried out by the Japanese Navy against the American mainland by using incendiary bombs to start forest fires and therefore divert American resources to fighting fires.

However, the bombs failed to cause a fire, rendering the operation more or less useless.

An interesting footnote to this story is that one of the pilots involved, Nobuo Fujita, returned to the town he bombed after the war to express his remorse, and was favourably received during his visit by the citizens of Brookings, Oregon.


Another attack I don't see mentioned here yet was on the SS Montebello off the Central California coast near Cambria. From Wikipedia:

SS Montebello was an oil tanker sunk by the Japanese submarine, I-21, off the coast of California on December 23, 1941.



Why didn’t the Japanese attempt even a single attack on the mainland? What deterred them from striking such a direct blow on America? A submarine attack would have been easy for them, but they never sent a known submarine beyond the territorial waters of Hawaii.

In addition to the other answers, I'll mention the I-400 class submarine. They were under water aircraft carriers and each carried 3 M6A seaplanes. They were conceived in 1942 as a way to bring more than just a submarine's one little deck gun to the US west coast.

The Japanese knew sending a surface fleet to raid the US west coast would be a nightmare. Going beyond Hawaii meant an extra 5000 miles round trip. 5000 miles of extra fuel tankers and logistics ships. 5000 miles of patrolling and very angry US aircraft, ships, and submarines. Even if successful those ships would be out of action for weeks while in transit. Their solution was the I-400.

The I-400 class married the stealth and operational range of a submarine with the strike range of small bombers. Instead of a normal submarine firing at the coastline with its little deck gun, the I-400 could launch three bombers which could head inland and attack vital industrial and transportation targets.

Unlike many Axis "super-weapons" this one worked! But also like many Axis super-weapons, it took too long to reach the battlefield and there weren't enough. 18 were planned, 3 were completed, only 2 entered service before the war ended.

The plan was to attack the Panama Canal and stem the tide of US ships flooding from the East Coast to the West. The Panama Canal was well guarded against conventional surface, air, or submarine attack. The thinking was that a fleet of I-400s could sneak up and launch its aircraft late at night. They could do this in 30 minutes. The aircraft would attack from an unexpected direction bypassing the defenses and having the element of surprise.

By the time they were completed the war was basically over. And like everything else in the Japanese arsenal it was planned to be sent on a suicide mission against the US fleet. But the elaborate plan failed and the submarines were captured at the end of the war.

There's a good documentary on the I-400 by World War II in HD Colour.

  • Attacking the Panama Canal would have been the next logical step after Pearl Harbour, but it would have had to happen soon after. I don't think there were such plans in the Japanese Navy.
    – Yves
    Nov 4, 2016 at 8:30
  • I think there may have been some awareness on the part of the Japanese as well after Midway, or certainly after Yamamotos death, that their naval codes were not entirely secure. Even if they could've amassed a surface fleet large enough to strike the West Coast in say late 1942, I don't think they would've had any confidence such a move wouldn't been seen coming a long way off.
    – MattyZ
    Jan 7, 2017 at 15:45

We must never forget that Germany and Japan, the Axis powers, were also developing nuclear weapons in WW2, but before the Axis could finish development and deploy their nuclear weapons or dirty bombs, the Allies won the war.

The German submarine U-234 was delivering nuclear materials from Germany to Japan when Germany surrendered. That German submarine was ordered to surrender by the German high command and the two Japanese officer passengers on that submarine committed suicide. https://en.wikipedia.org/wiki/German_submarine_U-234

The Japanese planned to use these nuclear materials to make dirty bombs since they had not yet been successful in completing an atomic bomb. The Japanese had already dropped biological weapons on China and planned to do the the same to the American West Coast. https://en.wikipedia.org/wiki/Operation_Cherry_Blossoms_at_Night

We rarely hear about Germany and Japans nuclear development efforts since they did not finish them in time to use them. Some say the Axis lost the nuclear arms race in WW2 because Germany discounted the value of theoretical physics over the applied sciences, thus allowing Jewish scientists to study theoretical physics before fleeing persecution in Germany leaving a knowledge gap while adding considerably to the Allies knowledge of in this area.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.