Although an airfield was under construction on Johnston, the only aircraft present on the island were Navy PBY patrol planes, usually anchored offshore.

Although it was too close to Hawaii to be amphibiously assaulted, it was near the major Japanese air base in the Marshall Islands.

The executive officer of the 1st Marine Defense Battalion, Major Francis B. Loomis Jr., had arrived on Johnston on December 7, 1941.

Following news of the Attack on Pearl Harbor, the civilian contractors already present on Johnston began building more emplacements for the Marines' guns and positions.

A Japanese submarine, 8,000 yards offshore, broke the surface and fired star shell clusters over Johnston.

[1] A Japanese submarine fired on Palmyra and a US Navy dredge, Sacramento, which sat in the atoll's lagoon.

Although they were isolated, the Marine, Navy, and civilian garrisons became the front line of Pearl Harbor's defense while it recuperated.