26 U.S. Navy Ships That Helped Decide the War in the Pacific

World War II was fought across oceans, continents, and islands, with some of the conflict’s most decisive battles taking place at sea. In the Atlantic, Allied ships fought to keep supply lines open against German U-boats. But in the Pacific, the war became a vast naval campaign fought across thousands of miles, from Pearl Harbor and Midway to Leyte Gulf, Iwo Jima, and Okinawa.

American ships played a central role in turning the tide. Aircraft carriers, battleships, cruisers, destroyers, submarines, and landing ships helped the U.S. Navy carry the fight across the Pacific and closer to Japan. These vessels protected troops, launched aircraft, hunted enemy ships, supported island invasions, and became symbols of America’s growing naval power during World War II.

Wars are thought of as near-peer conflicts, at least in the modern sense of the word. As such, Japan was very much a near-peer to the United States, at least in the early stages of the war. Japan had one of the most powerful navies in the Pacific at the start of the war.

There are a multitude of reasons, but it comes down primarily to resources. The United States had sources of raw materials like steel, rubber, gasoline, and so forth. These are all core elements needed to keep and maintain a navy. Japan had none of these readily accessible without trade or conquest in mind.

• Main armament: 5 x 6 in/.50-cal triple Mark 6 guns, 8 x 5 in/.50-cal Mark 8 guns, 16 x 1.1 in guns, 12 x 20 mm saluting guns, 1 depth charge rack
• Number built: 2
• First year launched: 1938
• Crew: 888

Only two St. Louis-class light cruisers, commissioned by the United States Navy in the late 1930s, were built – the USS St. Louis (CL-49) and USS Helena (CL-50). This class of ship was meant to improve on the Brooklyn-class with better combat survivability and anti-aircraft guns.

Originally designed to serve as convoy escorts, these warships featured Mark 6 guns, known for their accuracy and destructive capabilities. They were grouped into five triple turrets along their decks. This, along with a series of lower-caliber anti-aircraft guns, helped the class play a critical support role.

• Main armament: 3 x 200 mm/.55-cal triple guns, 8 x 130 mm/.25-cal anti-aircraft guns, 2 x 37 mm saluting guns
• Aircraft capacity: 4 (tied)
• Number built: 7
• First year launched: 1933
• Crew: 899

The New Orleans-class of heavy cruiser warships were originally constructed during the 1930s, before the war. Their primary armament consisted of nine .55 caliber guns mounted in three triple turrets, delivering long-range firepower against enemy vessels. Additionally, the cruisers were equipped with various secondary armaments, which provided support against aerial assaults.

• Main armament: 3 x 203 mm/.55-cal triple guns, 6 x 127 mm/.38-cal twin guns, 12 x 40 mm quad Bofors anti-aircraft guns, 24 x 20 mm Oerlikon anti-aircraft cannons
• Aircraft capacity: 4 (tied)
• Number built: 14
• First year launched: 1942
• Crew: 1,700

The USS Saint Paul (CA-73) entered WWII late in the conflict, but it was one of the more technologically advanced ships, as reflected in its armament. The USS Saint Paul had nine 203 mm-caliber cannons and 12 more 127 mm-caliber cannons flanked by Oerlikon anti-aircraft cannons. Historically, this ship is significant because it was in Tokyo Bay to participate in the formal surrender ceremony.

• Main armament: 10 x 203 mm/.55-cal guns, 4 x 127 mm/.25-cal anti-aircraft guns
• Number built: 2
• First year launched: 1929
• Crew: 653

The Pensacola class's primary firepower consisted of 10 203 mm guns mounted in four turrets, which provided substantial range and striking power during engagements. The secondary armament featured 127 mm dual-purpose guns complemented by an array of anti-aircraft weaponry. The lead ship of this class, the USS Pensacola, played a key role in aerial defense and rescue during the Battle of Midway.

• Main armament: 3 x 8 in /.55-cal triple guns, 8 x 5 in/.25-cal anti-aircraft guns, 2 x 47 mm 3-pounder guns, 4 x 40 mm quad Bofors anti-aircraft guns, 4 x 40 mm twin Bofors anti-aircraft guns, 17 x 20 mm Oerlikon anti-aircraft cannons
• Aircraft capacity: 4 (tied)
• Number built: 2
• First year launched: 1932
• Crew: 848

The Portland class's primary armament consisted of a series of 8-inch/.55 caliber guns mounted in triple turrets. Additionally, it was outfitted with an anti-aircraft defense system consisting of eight 5-inch/.25 caliber dual-purpose guns and a range of other smaller caliber machine guns.

• Main armament: As built: 3 x 8 in/.55-cal triple guns, 4 x 5 in/.25-cal anti-aircraft guns, 6 x 21 in torpedo tubes; 1941: 3 x 8 in/.55-cal triple guns, 8 x 5 in/.25-cal anti-aircraft guns, 2 x 47 mm saluting guns, 4 x 1.1 in/.75-cal anti-aircraft guns
• Aircraft capacity: 4 (tied)
• Number built: 6
• First year launched: 1929
• Crew: 621

The Northampton-class heavy cruisers were equipped with nine 8-inch/.55 caliber rapid-fire naval guns arrayed in triple turrets, which allowed them to engage enemy vessels from a significant distance. At the same time, these warships featured anti-aircraft weaponry, which included four 5-inch/.25 caliber guns and various smaller caliber machine guns acted as a deterrent against enemy aerial threats.

• Main armament: 9 x 305 mm guns, 12 x 127 mm dual purpose guns, 56 x 40 mm guns, 34 x 20 mm guns
• Aircraft capacity: 4 (tied)
• Number built: 2
• First year launched: 1943
• Crew: 2,251

The Alaska-class was one of the most heavily armed U.S. Navy cruisers, with 200 mm-caliber cannons, some of the biggest at the time. The USS Alaska (CB-1) was key in covering the carriers Yorktown, Intrepid, Independence, and Langley as they advanced toward Japan in March 1945. Over the first month of this operation, the ship is credited with downing 12 Japanese aircraft.

• Main armament: 4 x 13 in/.35-cal, 8 x 8 in/.35-cal, 4 x 6 in/.40-cal, two Colt gatling guns, 3 torpedo tubes
• Number built: 3
• First year launched: 1893
• Crew: 473

The Indiana class is perhaps the oldest class of any warship to participate in WWII – it was one of the United States' first true battleship classes built before the turn of the 20th century. These ships' main weapon was the four 13-inch/.35 caliber guns mounted on the hull, flanked by a series of lower-caliber guns and torpedo tubes. The USS Oregon (BB-3) Indiana-class ship was nearly scrapped under the Washington Treaty but ultimately saved and later saw duty, primarily cargo transport, in WWII.

• Main armament: 5 x 14 in twin guns, 21 x 5 in single guns, 4 x 21 in torpedo tubes
• Number built: 2
• First year launched: 1912
• Crew: 1,042

The first New York-class battleship was built in 1912, and some of its weaponry lagged more current ships. Its primary armament consisted of 10 14-inch/.45 caliber guns split into five twin-gun turrets. As secondary armament, these ships carried 21 5-inch/.51 caliber guns were versatile weapons for engaging smaller vessels and aircraft.

• Main armament: 10 x 14 in/.45-cal guns, 21 x 5 in/.51-cal guns, 4 x 21 in torpedo tubes
• Number built: 2
• First year launched: 1914
• Crew: 864

The Nevada-class battleships' primary weaponry consisted of 10 14-inch/.45 caliber guns. These warships were equipped with 21 5-inch/for anti-aircraft and supplementary fire.51-caliber guns. These ships are considered some of the first "standard battleships" built in the era of WWI. One ship of the class was sunk in the Pearl Harbor bombing, and the other, though badly hit, would see action later in the war.

• Main armament: 12 x 14 in/.50-cal, 14 x 5 in/.51-cal, 2 x 21 in torpedo tubes
• Number built: 3
• First year launched: 1917
• Crew: 1,084

The New Mexico-class battleships' primary armament consisted of 12 14-inch/.50-caliber guns strategically arranged in four triple turrets, delivering a powerful and concentrated barrage. Complementing the main armament, these warships featured 5-inch/.51-caliber secondary guns to defend against closer surface threats and torpedo boats. These battleships were also equipped with an array of anti-aircraft guns and torpedoes to protect the fleet from aerial and underwater attacks.

• Main armament: 4 x 14 in triple guns, 14 x 5 in single guns, 4 x 3 in single guns, 2 x 21 in torpedo tubes
• Number built: 2
• First year launched: 1919
• Crew: 1,083

The Tennessee-class battleships were equipped with 12 14-inch/.50 caliber guns as their primary armament, mounted in four triple-gun turrets. The USS Tennessee (BB-43) was the lead ship of this class of two and was present at the bombing of Pearl Harbor. It suffered some damage and needed a major overhaul.

However, the USS Tennessee would return with upgraded combat systems and sink the Japanese battleship Yamashiro in the Battle of Surigao Strait. The ship participated in the bombardment of Okinawa and was hit by a suicide plane but remained in action for almost another month before returning for more repairs.

• Main armament: 4 x 360 mm/.45-cal triple guns, 12 x 130 mm/.51-cal guns, 12 x 130 mm/.25-cal anti-aircraft guns
• Aircraft capacity: 3 (tied)
• Number built: 2
• First year launched: 1915
• Crew: 915

The Pennsylvania-class battleships' main battery consisted of 12 14-inch/.45 caliber guns arranged in four triple-gun turrets. Their secondary armament featured 5-inch/.51 caliber guns designed for quick firing against smaller vessels and airborne threats. This class was equipped with various anti-aircraft weapons, and over time, ships were retrofitted with advanced fire control systems to increase their striking power and defensive capabilities.

• Main armament: 9 x 406 mm/.45-cal Mark 6 guns, 16 x 127 mm/.38-cal DP guns, 68 x 40 mm guns, 76 x 20 mm guns
• Number built: 4 (tied)
• First year launched: 1941
• Crew: 2,364

The South Dakota-class battleships were developed in the late 1930s and launched just in time for the war. Considering their later development, these warships were equipped with larger guns than previous generations of battleships. This class was outfitted with nine 16-inch/.45 caliber Mark 6 guns, housed in three triple turrets. Additionally, these vessels carried an array of anti-aircraft armaments, including 127 mm/.38 caliber guns, various smaller caliber weapons and machine guns.

• Main armament: 8 x 16 in/.45-cal Mark 1 guns, 12 x 5 in/.51-cal guns, 4x3in/0.23-cal guns, 2x21in torpedo tubes
• Aircraft capacity: 4 (tied)
• Number built: 4
• First year launched: 1920
• Crew: 1,080

The primary weaponry of the Colorado class consisted of 16-inch/.45 caliber guns. Complementing the primary guns were 5-inch/.51 caliber secondary guns were meant for combating smaller enemy vessels and weak points on enemy warships.

This class was outfitted with an array of anti-aircraft weapons, providing some defense against close aerial threats and two torpedo tubes for dealing with other enemy vessels.

• Main armament: 9 x 16 in Mark 6 guns, 20 x 5 in/.38-cal guns, 16 x 1.1 in machine guns
• Number built: 2
• First year launched: 1940
• Crew: 1,880

The North Carolina-class battleships boasted an array of armaments that solidified their position as formidable warships. Their primary armament consisted of nine Mark 6 16-inch/.45-caliber guns as well as 5-inch/.38-caliber dual-purpose guns for anti-aircraft and surface engagement capabilities. There were a series of smaller caliber guns that served in defensive roles.

The USS North Carolina was the lead ship of its class and had an impressive service record throughout the war, recording 15 battle stars. Also, during the Battle of the Eastern Solomons, the ship is said to have shot down between seven and 14 Japanese aircraft.

• Main armament: 3 x 16 in/.50-cal triple Mark 7 guns, 20 x 5 in/.38-cal Mark 12 guns, 80 x 40mm/.56-cal Bofors anti-aircraft guns, 49 x 20 mm/.70-cal Oerlikon anti-aircraft guns
• Aircraft capacity: 3 (tied)
• Number built: 4
• First year launched: 1942
• Crew: 1,921

The Iowa-class battleships' primary armament consisted of 16-inch/.50 caliber Mark 7 guns, capable of accurately firing 2,700-pound armor-piercing shells across distances up to 23 miles. This class also had a variety of secondary and anti-aircraft weaponry, including a combination of 40 mm Bofors anti-aircraft guns and 20mm Oerlikon cannons.

• Main armament: 1 x 5 in/.51-cal gun, 2 x 3 in/.50-cal gun
• Aircraft capacity: 21
• Number built: 1
• First year launched: 1940
• Crew: 970

The Long Island-class escort carrier only had one ship within its class, the USS Long Island (CVE-1). As an aircraft carrier, the armament for this ship was not especially impressive. However, the 21 aircraft that this vessel could launch were capable of incredible damage with their payloads. As for the actual armament, the USS Long Island had a 5-inch/.51 caliber gun and two 2-inch/.50 caliber guns.

• Main armament: 1942: 2 x 5 in/.51-cal guns, 10 x 20 mm Oerlikon anti-aircraft cannons; 1945: 2 x 5 in/.38-cal guns, 8 x 40 mm twin Bofors anti-aircraft guns, 20 x 20 mm Oerlikon anti-aircraft cannon
• Aircraft capacity: 24
• Number built: 45
• First year launched: 1941
• Crew: 890

The Bogue-class of escort carriers was headed by the USS Bogue (CVE-9), which played a critical role in the Hunter-Killer practice of hunting and destroying submarines. Along with a complement of high-caliber weapons and anti-aircraft cannons, the USS Bogue hosted 24 aircraft capable of spotting and bombing submarines. Throughout the war, the USS Bogue sank 10 German submarines and two Japanese submarines while reportedly damaging at least seven more submarines.

• Main armament: 1 x 5 in/.38-cal DP gun, 8 x 40 mm twin Oerlikon cannons, 28 x 20 mm Bofors anti-aircraft guns
• Aircraft capacity: 28
• Number built: 50
• First year launched: 1943
• Crew: 860

The Casablanca class was WWII's most widely produced escort carrier, with 50 entering the service. The primary armament was a 5-inch/.38 caliber gun, flanked by 40 mm Oerlikon cannons and 20 mm Bofors anti-aircraft guns, provided aerial defense in intermediate and close ranges. These escort carriers could host 28 aircraft, commonly Grumman F4F Wildcats or Hellcats.

• Main armament: 24 x 40 mm Bofors guns, 22 x 20 mm anti-aircraft guns
• Aircraft capacity: 30
• Number built: 9
• First year launched: 1942
• Crew: 1,569

The Independence-class aircraft carriers were introduced in the later years of WWII. Like most aircraft carriers, they were not heavily armed but their destructive capability lay with the aircraft they hosted.

Their air wings, composed of fighter, bomber, and torpedo aircraft, delivered powerful airborne firepower across land and sea. Additionally, these carriers were equipped with anti-aircraft guns, such as the 40 mm Bofors, which provided reliable protection against aerial threats.

• Main armament: 8 x 5 in/.25-cal guns, 4 x 1.1 in anti-aircraft guns, 24 x .50-cal machine guns
• Aircraft capacity: 80
• Number built: 1
• First year launched: 1939
• Crew: 1,800

The Wasp-class of aircraft carriers had only one ship, the USS Wasp (CV-7). The primary guns on this aircraft carrier included eight 5-inch/.25 caliber guns, four 1.1-inch anti-aircraft guns, and 24 .50 caliber machine guns.

The USS Wasp was home to 80 aircraft, including fighters, bombers, and more. However, it did not survive the war, being sunk in the Battle of Guadalcanal. The ship was awarded two battle stars.

• Main armament: 8 x 5 in/.25-cal anti-aircraft guns, 40 x .50-cal machine guns
• Aircraft capacity: 86
• Number built: 1
• First year launched: 1933
• Crew: 2,461

The USS Ranger (CV-4) is the only aircraft carrier of its class and was host to 86 aircraft. Like many other aircraft carriers, the USS Ranger relied on other ships for the big guns, and as such, its armament was relatively weaker compared to cruiser or battleship classes.

The primary weapons on the USS Ranger were a series of eight 5-inch/.25 caliber guns, flanked by forty .50-caliber machine guns. While this carrier was not as celebrated as other classes, it still earned two battle stars throughout the war.

• Main armament: 4 x 5 in/.38-cal twin guns, 4 x 5 in/.38-cal singe guns, 8 x 1.6 in/.56-cal quad guns, 46 x 0.8 in/.78-cal anti-aircraft guns
• Aircraft capacity: 90 (tied)
• Number built: 24
• First year launched: 1942
• Crew: 2,600

The Essex class was an iconic group of aircraft carriers vital to the United States Navy during WWII. The primary anti-aircraft weaponry consisted of 12 5-inch/.38 caliber twin guns placed strategically around the ship to provide maximum coverage.

Additionally, the Essex class carriers hosted 90 aircraft. The lead ship of this class, the USS Essex, played a vital role in the landings at Iwo Jima and the campaign against Okinawa.

• Main armament: 8 x 5 in/.38-cal guns, 4 x 1.1 in/.75-cal machine guns, 24 x .50-cal machine guns
• Aircraft capacity: 90 (tied)
• Number built: 3
• First year launched: 1936
• Crew: 2,217

Like the other carriers on this list, the Yorktown-class aircraft carriers relied predominantly on their fleet of aircraft rather than their own physical armaments. Still, these vessels were armed with dual-purpose 5-inch/.38 caliber guns, complemented by a series of 1.1-inch/.75 caliber machine guns serving an anti-aircraft role.

As the war progressed, the carriers saw upgrades to their anti-aircraft arsenal, adding 20 mm Oerlikon and 40 mm Bofors anti-aircraft guns, enhancing their capabilities to defend against rapidly evolving aerial threats. The USS Enterprise (CV-6) is perhaps the most famous carrier in this class, boasting the most battle stars of any vessel in WWII.

• Main armament: 4 x 8 in/.55-cal twin guns, 12 x 5 in anti-aircraft guns
• Aircraft capacity: 91
• Number built: 2
• First year launched: 1925
• Crew: 2,122

The Lexington-class aircraft carriers were some of the largest in the U.S. Navy by crew, number of aircraft at 90, and size. These carriers were designed with four 8-inch/.55 caliber twin guns and lower caliber anti-aircraft guns. Lexington-class ships were originally intended as battlecruisers in the early 1920s but were later outfitted as aircraft carriers.

The lead ship of this class, the USS Lexington, played a key role in the Battle of Coral Sea when its air group scored the first sinking of the battle, destroying the Japanese ship Soho. However, the ship would not survive the war, as it was sunk in May 1942.