Ever since World War II, American teams have played in European Leagues (usually in US Army Leagues stationed around the World), or have played matches against teams from around the World (usually Under 19/20 representative teams from the USA).
Additionally the National Football League has played a number of games outside of USA, notably the matches against Canadian Football League opposition from 1950-1969, and the American Bowl / International Series of matches between NFL teams played in cities around the World.
A third feature of American Football on the World stage is the Professional Leagues played in Europe & North America which have attempted to be a World League.
Finally there is the American Football World Cup, first held in Italy in 1999, and other World Competitions such as American Football at the World Games or International matches between countries from around the World.
World Football Leagues Era (1991-present):
Early European Leagues which failed to get off the ground:
International League of American Football 1990: https://eirball.ie/2020/02/23/international-league-of-american-football-1990/
European Pro Leagues Era:
Global South / Indoor Pro Leagues Era:
AAA World Football Leagues (Seasons):
International League of American Football (Seasons): 1990
American Football League of Europe (Seasons): 1995
China Arena Football League (Seasons): 2019
 Irish American Football Association (2018) Nostalgia – A look a some pictures from the archives [Internet] Available from: http://www.americanfootball.ie/wp-content/uploads/2017/10/20171016_165339-1024×768.jpg [Accessed 3 July 2018]
 Brian O’Reilly – Irish Independent (2014) February 13 2014: Video: Irish woman becomes star of Australia’s Lingerie Football League [Internet] Availabble from: https://cdn-03.independent.ie/videos/article30006990.ece/fd099/AUTOCROP/h342/West%20Cork’s%20Linda%20Holland%20on%20reaching%20football’s%20largest%20stage%20in%20Australia%20(Generated%20thumbnail) [Accessed 29 November 2019]