The government of Portugal recognised Swiss neutrality in 1815. At this time too, consular relations were established between the two countries, even though the first formal agreement was only signed in 1883.
Switzerland opened a consulate in Lisbon in 1817, which was upgraded to a consulate general in 1874. A Swiss diplomatic chancery was established in the Portuguese capital in 1936, and was upgraded to a legation in 1945 and an embassy in 1959. Portugal first established a consulate in Switzerland in 1855 in Geneva. A Portuguese legation was set up in Bern in 1892, and was replaced by an embassy in 1959.
Membership of both countries of the European Free Trade Association (EFTA) served to foster intergovernmental relations in the period between 1960 and 1985. From 1963 to 1975, Switzerland represented Portuguese interests in Senegal.
Reciprocal visits became more frequent as of 1977. President of the Swiss Confederation Pascal Couchepin visited the Portuguese president in 2003, as did Federal Councillor Samuel Schmid in 2004 and 2006, and Swiss President Micheline Calmy-Rey in 2007. On 17–18 October 2016, President Marcelo Rebelo de Sousa of Portugal paid a state visit to Switzerland, and Swiss President Doris Leuthard returned the visit from 28–29 November 2017.
Portugal, Historical Dictionary of Switzerland (de, fr, it)