NUMAST traced its roots back more than 150 years, when the Mercantile Marine Service Association was founded in 1857 in response to the harsh laws of the 1850 Merchant Shipping Act.
In 1936, the MMSA merged with the Imperial Merchant Service Guild and retained its name.
Meanwhile, the Association of Wireless Telegraphists was established in 1912 in response to the growing use of telegraphy at sea.
Mergers and name changes down the years culminated in the formation of the Radio and Electronic Officers' Union (REOU) in 1967.
The Navigating & Engineer Officers' Union (NEOU) was born in the mid-1930s and in 1956, following more than a decade of cooperation on issues of common concern, the MEA and the NEOU joined to form the Merchant Navy & Airline Officers' Association (MNAOA).