Search one of the following locations to find a hidden sandcastle:

Guadalcanal: There are two islands (a small one and a big one). On the big island is a beach facing toward Guadalcanal as well as two trees. Follow the beach to the left of those trees to find a mini sandcastle with a shovel.

Iwo Jima: On the island closest to the carrier is a small sandcastle facing the carrier.

Wake Island: There are two small islands by the beach base. On the one to the right is a sandcastle with a Swedish flag and a yellow shovel.