The Society was formed on 18 March 1818, as the Port of London Society. Following mergers with two other societies, the name was changed to The British & Foreign Sailors Society. In 1925 it was changed to The British Sailors Society. In 1995 the name was changed to The British & International Sailors Society. The most recent name change took place on 1 December 2007 when the present name was adopted.
The Society is an interdenominational charity and has close links with many of the mainstream Protestant Churches in the United Kingdom, such as the Baptist Union, Church of Scotland, United Reformed Church, and the Methodist Church. The charity's head office is in Southampton, England.
The Society is international and in addition to its presence in the UK it operates in Australia, Belgium, Brazil, Curaao, Ghana, Runion, Russia, India, Indonesia, Madagascar, the Philippines and Ukraine.
The Society has port chaplains and seafarers' welfare centres at various ports around the world. It also has one retirement home - in Greenock, Scotland. Within the UK the Society has a presence at Aberdeen, Arbroath, Dundee, Felixstowe, Grangemouth, Leith (port of Edinburgh), Manchester Ship Canal, Milford Haven, Montrose, Portland, Dorset, Port Talbot and South Wales Ports, Portbury (near Bristol), Seaham (County Durham), Southampton and the Wirral (Mersey).
In New Zealand, an independent Society, the International Sailors Society New Zealand Incorporated, coordinates the activities of six independent seafarers' welfare organisations (all registered charities) in the ports of Auckland, Bluff, Dunedin (Otago), New Plymouth (Taranaki), Bay of Plenty (Mt Maunganui) and (since 2011) Wellington. Another in Lyttelton recently (2009) went into recess. The Sailors Society in New Zealand is linked to the Sailors Society (UK) but is self-governing and self-supporting.
Independent bodies, similarly linked to the UK, also exist in South Africa and Canada.
The British Sailors Society also ran a Children's Home. "Lagarie House" was known as Lagarie Children's home. The home was on the banks of the Gareloch on the outskirts of the village of Rhu, by Helensburgh. The society ran the home from October 1969 until it closed in 1982. Lagarie House was built in 1901 by the renowned architect Alexander Nisbet Paterson (1862-1947). Basically a mansion, it had a large dining room, three reception areas, offices and staff break rooms. It had a total of six dormitories and large bedrooms. The home was intended for use by seafarers whose families were in need of help with their children, be it to give the parents respite during a family crisis or in some cases a home due to the loss of a family member and the father could not manage and go to sea at the same time. It was also used to allow a seafarer to take his wife away with him for a trip while he worked. At one stage up to 60 children being cared for. The home was ran on purely charitable income.