キュナード・ライン
Rostron joined the Cunard Line in January 1895 and earned a position as fourth officer on the ocean liner . In the years afterward he would serve on other Cunard ships including the "Aurania", "Etruria", "Servia", "Cherbourg", "Ultonia" and "Saxonia". As a member of the RNR, Rostron regularly attended training at HMS "Excellent" (including in September 1902). He temporarily left the Cunard Line to serve with the Royal Navy during a period of international tension occasioned by the Russo-Japanese War of 1904–1905.