Troubridge was promoted to the rank of commander in 1895, serving with the Mediterranean Fleet aboard the flagship of the fleet's second in command, , initially Rear-Admiral Sir Robert Harris, and later Rear-Admiral Sir Gerard Noel. He was promoted to captain 17 July 1901 and went on to serve as a naval attaché to several powers, based at first in Vienna, and from 1902 in Madrid. He became a naval attaché in Tokyo later in 1902, and served as such until 1904. With the outbreak of the Russo-Japanese War he went to sea with the Japanese warships and was present at the Battle of Chemulpo Bay and the subsequent operations off Port Arthur. After the conclusion of the war Troubridge was awarded the Order of the Rising Sun by the Japanese, while the British government appointed him a Companion of the Order of St Michael and St George and a Member of the Royal Victorian Order. He took command of the battleship , serving as flag captain to the commander of the Mediterranean Fleet, Admiral Sir Charles Drury.