Which Oceanian country's flag includes a Union Jack and a shield with a lion? Fiji. Its national flag combines a light-blue field, the Union Jack in the canton, and a shield adapted from Fiji's national coat of arms.
The shield was granted by royal warrant in 1908, during Fiji's British colonial period. The lion at the top holds a cocoa pod, linking the emblem to both British heraldic influence and Fiji's agricultural economy. The shield's other sections show sugar cane, a coconut palm, a dove of peace, and bananas.
Fiji adopted the flag on 10 October 1970, the day it became independent. Although Fiji became a republic in 1987, the flag remained unchanged. A proposed redesign was abandoned in 2016, partly after national celebrations surrounding Fiji's first Olympic gold medal under the existing flag.
Australia, New Zealand, Tuvalu, and several other Pacific flags also retain the Union Jack, so the shield is the key clue. Fiji is unusual because it is the only republic among those independent countries with a Union Jack on its national flag.