In December, the Japanese declaration of war saw Yarra reassigned to Southeast Asia. She left Alexandria on 9 December and reached Java on 11 January 1942, where she commenced convoy escort duties. On 5 February, the sloop escorted a convoy to Singapore; the last convoy to arrive before the city was captured by the Japanese.
In December of 1942, Japan's declaration of war led to Yarra being reassigned to Southeast Asia. She departed Alexandria on December 9th and arrived in Java on January 11th, where she began escorting convoys. On February 5th, the sloop escorted a convoy to Singapore, which was the last convoy to reach the city before it fell to Japanese forces.