[1] Bought by shipping giant P&O around the time of World War I it was sold in 1972 to an Australasian consortium and closed at the end of the twentieth century.

After Jones’ death in 1869 Mills tried twice to float a Union Steam Ship Company of New Zealand Limited without attracting enough interest from local investors but in 1875 he found backing from Scottish shipbuilder Peter Denny in return for Union Steam Ship orders for Denny's Dumbarton shipyard.

[1] It steadily mopped up trans-Tasman and coastal shipping businesses including - In 1878 McMeckan and Blackwood, who ran a weekly service between Melbourne and New Zealand, sold Albion, Arawata, Tararua and Ringarooma to Union.

The Union Steam Ship fleet was described as 74 high class steamers with a tonnage of 237,860 and of an average age of 12 years.

He succeeded David Aiken as general manager in March 1934 and was appointed chairman in January 1936 on the death of founder Sir James Mills.

[19] Union in conjunction with Holyman's Airways and Huddart Parker set up an airline across Bass Strait which began business in September 1934.

In 1935 they added Adelaide Steamship Company as a partner in the venture which was renamed Australian National Airways the following year.

Union was instrumental in establishing this business in particular by buying the first three flying boats which began operations in April 1940.

[24] At the end of the 20th century Brierley Investments bought all the shares, broke Union Steam Ship into components and sold up what it could.

Union Steam Ship began regular sailings between Wellington and Lyttelton in 1895 with the Penguin making two round trips a week.

[26] TEV Wahine entered service in October 1966 and foundered and sank at the mouth of Wellington Harbour 18 months later in April 1968.

[25] In what has been described as "a fatal mistake",[27] the Union Steam Ship announced in 1956 that the Tamahine was to be withdrawn from the Wellington-Picton route in 1962 and unlikely to be replaced (despite an offer of a $3 million government loan).