In the spring of 1942, things weren’t going well for the Allies, especially for the Americans in the Pacific. After the crippling sneak attack at Pearl Harbor, the Japanese invaded Wake Island, the Philippines, Burma, Malaya, and the Dutch East Indies, and had American and Filipino forces bottled up at Corregidor. 

The Japanese were ready to keep pushing southwest and had their eyes set on capturing Port Moresby in New Guinea. This would isolate Australia and it would open up even more avenues for the Empire of Japan. But Japanese leaders, flush with success, and the ease with which it had been achieved, were undecided of where to move next. 

Admiral Nagano and the Naval General Staff wanted a westward expansion towards Ceylon, India, or towards Australia. Admiral Yamamoto and the Combined Fleet thought the only way for Japan to defend her interests would be the destruction of the American aircraft carriers. He suggested that they move against Midway and then threaten Hawaii where the American carrier fleet could be dealt a death blow. 

But things changed in April when the inconceivable happened. Japan, and Tokyo itself, were bombed by Jimmy Doolittle and Nagano ordered Yamamoto to proceed with his Midway plan with a feint in the Aleutian Islands. However, the planned operation for Port Moresby and Tulagi had progressed too far to be called off. So, the Imperial Fleet would be running concurrent operations. This would overextend the Japanese forces. 

Operation MO, the operation against Port Moresbly, called for the invasion of the Port and then for an advance towards New Caledonia, Fiji, Samoa, and Tulagi. 

The Japanese didn’t expect any large Allied fleet in the area and no carriers other than the American carrier Saratoga. They were confident that they would easily dispatch any Allied fleet that entered the Coral Sea to stop them. They had two powerful aircraft carriers the Shokaku and the Zuikaku and the light carrier Shoho.

Port Moresby wasn’t just important to the Japanese however. Admiral Chester Nimitz, the Commander-in-Chief of the United States Pacific Fleet (CINCPAC), needed it not just for the defense of Australia, but as a springboard for future moves in the southwestern Pacific. 

The Americans had broken the Japanese codes and knew what their intentions were. However, countering them was another story: The Saratoga wasn’t in the Coral Sea but in Puget Sound undergoing repairs. And aircraft carriers Enterprise and Hornet hadn’t returned from the Doolittle Raid in time. So, Nimitz, keenly aware that Douglas MacArthur would control the land-based aircraft, had to send his own ships there. Nimitz dispatched the air groups of the Yorktown and Lexington. 

The Yorktown Task Force 17 included the heavy cruisers Astoria, Chester, and Portland, six destroyers, and the tanker Neosho. The Lexington Task Force 11 consisted of the heavy cruisers Minneapolis and New Orleans and five destroyers. 

On May 4, the Yorktown launched strikes on the Japanese forces that had invaded Tulagi. It irreparably damaged a destroyer, sunk three minesweepers and four landing barges. As each side maneuvered toward each other, they were each unaware of the exact location of the opposing fleet. 

The Japanese sighted what they thought was an aircraft carrier but it was the tanker Neosho and the destroyer Sims. Twenty dive bombers scored seven direct hits turning the ship into a blazing inferno but she drifted for four days until the surviving crew abandoned her and she was scuttled. The Sims took three direct bomb hits, two of which to the engine room. The keel buckled and the Sims sank quickly along with 379 members of her crew. 

American scout planes had sighted several Japanese ships and Admiral Fletcher launched 93 aircraft in an attack of his own. Arriving at where they thought the enemy’s fleet was, they spotted the carrier Shoho about 20 miles away. Shoho was blasted by 13 bomb and seven torpedo hits and was set hopelessly ablaze. She sunk by 1135 hours. Back on the Lexington, the radio room could hear the chatter of Lieutenant Commander Dixon of a Dauntless dive bomber squadron, “Scratch one flattop… Dixon to carrier, scratch one flattop.”

At midnight, the Japanese postponed the invasion for two days. 

On the 8th of May, the battle still raged. Each side launched carrier aircraft to attack the other. Pilots from the Yorktown spotted the Japanese carrier Shokaku and hit her with two bombs just before 1100 hours. One penetrated the flight deck forward of the starboard bow and set fire to the fuel. The other hit aft. Although she could still receive aircraft, Shokaku couldn’t launch any. 

The Japanese found the American fleet at 1118. Yorktown skillfully avoided eight torpedoes, but the dive bombers scored a direct hit which penetrated down to the fourth deck; yet, she was able to continue with flight operations. Lexington was hit by a torpedo at 1120 that was quickly followed by another. She was also hit by two small bombs.

The hits from the torpedoes were handled by damage control parties and the listing of the ship was countered by shifting oil ballast. It appeared that she would live to fight another day and she began to receive returning aircraft. 

However, at 1247 hours, a massive explosion shook the ship. Fuel vapors from a generator that had been left running ignited. Several other explosions followed. At 1445 hours, another massive explosion put the fires out of control. At 1710, the order was given to abandon ship. It was an orderly rescue and even the ship’s dog was saved. At 1956 hours the destroyer Phelps launched seven torpedoes to scuttle the Lexington and at 2000 hours she sank with a final explosion. The Battle of the Coral Sea was over. 

Tactically, the battle was a victory for the Japanese. They had sunk the Lexington, Sims, and Neosho while only losing the light carrier Shoho and some smaller craft at Tulagi. Strategically, however, it was an American victory. The invasion of Port Moresby was stopped and the damage to the Shokaku and the air groups of the Zuikaku effectively kept both out of the upcoming Midway battle.

The overconfident Japanese had been stopped for the first time in the war. The next month at Midway, they’d suffer catastrophic losses that would turn the war’s tide. 

The operation in the Coral Sea would be the first in naval history where the two opposing fleets never saw each other and all of the combat operations would take place by aircraft.