On the outbreak of war in August 1914, she was seized whilst in Port Said, Egypt and was requisitioned for service under the Red Ensign of the British Merchant Marine in January 1915 to operate seaplanes.

The ship was hit by one torpedo in the Number 1 cargo hold; this was full of timber which limited water ingress and saved her from sinking.

[4] She rendezvoused with Jeanne d'Arc and the French pre-dreadnought battleship Jauréguiberry around 13 August and observed while they bombarded Turkish installations in Haifa.

[5] In early September, the ship assisted the French as they evacuated Armenian troops and civilians from Alexandretta and the surrounding area and then resumed her earlier work of reconnaissance and espionage.

In January 1916, she was assigned to the East Indies and Egypt Seaplane Squadron together with the carriers Empress, Ben-my-Chree and Raven II.

The East Indies and Egypt Squadron reassembled in late August with Raven II, Anne and Ben-my-Chree and the aircraft from the three carriers attacked the Turkish supply dump at El Afule for thirty minutes.

Despite the loss, her aircraft bombed Turkish installations at Tull Keram, Nablus, Ludd and Ramleh before returning to Port Said on 27 August.

[9] A few days later, Anne replaced Raven II, after that ship had been damaged by an air attack on 1 September, on an expedition into the Red Sea to support the Arab Revolt against the Turks.

She rendezvoused with the elderly cruiser HMS Fox and Dufferin of the Royal Indian Marine (RIM) and they arrived at Rabigh on 9 September.

The ship briefly ran aground off Yenbo, but got off and was able to observe for Fox and Hardinge of the RIM as they shelled Turkish positions near Wejh on 13 September.

Aside one brief visit to Suez to recoal, Anne remained in the area while her aircraft flew bombing and reconnaissance missions until she was relieved by Raven II on 26 October.