Capture of Eniwetok would provide an airfield and harbor to support attacks on the Mariana Islands to the northwest.

Eniwetok is a large coral atoll of 40 islands with a land area total less than 5.85 square kilometres (2.26 sq mi).

It has a mean elevation above sea level of 3 metres (9.8 ft)[2] and surrounds a deep central lagoon, 80 kilometres (50 mi) in circumference.

When the Gilbert Islands fell to the United States in late 1943, the Imperial Japanese Army assigned defense of Eniwetok to the 1st Amphibious Brigade, recently formed from reservists of the 3rd Independent Garrison in Manchukuo, 3,940 men under the command of Major General Yoshimi Nishida,[1]: 32  first arriving on 4 January 1944.

On 17-18 February 1944, Vice Admiral Raymond A. Spruance executed Operation Hailstone, an American carrier strike against the Japanese base at Truk in the Caroline Islands[1]: 67  destroying 39 warships and more than 200 planes.

The island is triangular in shape, with a palm grove on its eastern side and an airfield across its north half.

Engebi received 692 men from the brigade and 54 naval personnel, commanded by Colonel Toshio Yano.

Naval bombardment of Eniwetok began on 17 February, and at 13:18 US forces landed on Canna and Camelia islets, near Engebi.

There they found evidence that Parry and Eniwetok Islands were more heavily defended than expected, so the battle plan was adjusted.

On the island the Japanese had 779 Army troops, 24 civilians, and five naval personnel, all under the command of Lieutenant Colonel Hashida Masahiro.

At 07:10 on 18 February two cruisers and two destroyers opened fire on Japanese positions from the lagoon side of Eniwetok.

The short naval bombardment left many Japanese positions intact, and the American LVTs could not scale an 8 feet (2.4 m) sand dune just inland.

A Japanese counter-attack, carried out by 300–400 men, hit the western part of the American line, which was supported by mortar fire.

[1]: 77  The Marine commander, Colonel Ayers, ordered that the attack continue through the night to eliminate the Japanese pocket in the northwest corner.

The Japanese defences consisted of a series of eight strong points along the beach, protected by trenches and a network of foxholes.

The landing occurred at 09:00[1]: 80–81  with a combined force of Marines and tanks advancing rapidly past Japanese positions once machine-gun fire had been suppressed, followed by demolition and flame-thrower squads clearing out spider holes and Japanese defenders who had been bypassed, followed by three four-man squads mopping up any survivors.

[1]: 83  The vast majority of Japanese soldiers were killed, including General Nishida, although 105 survivors were captured.