Located south of Rennell Island. They based occasional E13A Jake seaplanes there (2 or 3 days at a time). These planes searched 'Torpedo Alley' area, south-east of San Cristobal. The Americans caught on to this and sent a few missions to try and get them.

October 1942
I-15 is refueling floatplanes at the Indispensable Reef.

October 18, 1942
The I-26 arrives at the Indispensable Reef. Early in the morning, two Aichi E13A1 "Jakes" arrive. After one E13A1 departs, an enemy patrol aircraft flies over the reef. The second Jake takes off immediately. The I-26 crash-dives. She damages her three lower torpedo tubes on a reef, but manages to float free.

October 22, 1942
Indispensable Reef. Early in the morning, the I-26 refuels three E13A1 "Jakes". One of the planes later sights the USS WASHINGTON (BB-56) heading north.

October 23, 1942
Indispensable Reef. Early in the morning the I-26 refuels another "Jake" which manages to locate an enemy convoy.

October 25, 1942
Indispensable Reef. A Boeing B-17 bomber arrives over the reef. The I-26 dives and cannot refuel aircraft that day.

October 26, 1942
The I-26 departs the area. She is to be replaced by the I-122.

Early September 1942
I-122 refuels seaplanes at Indispensable Reef

Nakajima B5N Kate Tail Number EI-306
Force landed on the reef, discovered and salvaged

Nakajima B5N Kate Tail Number EI-302
Force landed on the reef, discovered and salvaged