The ship also had an extensive engineering workshop on board and could provide repair support to Italian submarines based in East Africa.

Following Italy's declaration of war on 10 June 1940, colonial ship Eritrea became part of the Italian Royal Navy (Regia Marina).

[4] In February 1941, as the East African Campaign started to go badly for the Italians, Massawa, the home port for Eritrea became more endangered.

In December 1941, after the official declaration of war, the Japanese government allowed Eritrea to provide assistance to "transport submarines."

These submarines, carrying rare goods, arrived in Japanese-held Penang and Singapore from the distant bases in German-held Bordeaux.

On 8 September 1943, when Italy declared an armistice, Eritrea was navigating between Singapore and Sabang to give a support to the Italian oceanic cargo submarine Comandante Cappellini.