You might think that playing in a full international for two different countries was a rare distinction. However, the list below shows that it is hardly the case.
I have only included players who played matches for both their countries before our 1937 cut off point (which excludes the German Austrian anchluss players). I have also excluded the Irish players who represented Ireland and Northern Ireland or The Irish Free State.
Great Britain.
John Hawley Edwards (England-Wales)
Shrewsbury born John Hawley Edwards played for Shropshire Wanderers and The Wanderers. He was called in as a late replacement in England's third ever international against Scotland in Glasgow in 1874. He was the first treasurer of the Football Association of Wales and played in Wales' first ever international, also against Scotland in Glasgow, on 25th March 1876.
Jack Reynolds was born in Blackburn but spent much of his youth in Ireland, his father being a soldier. Later Reynolds himself joined the army and was posted to Ireland. Whilst there he played for Distillery- they were impressed enough to buy him out of the army and he began his career as a professional footballer. The Irish Football Association were under the impression that Reynolds was an Irishman and when they selected him for the national team, he didn't tell them any different. He played 5 matches for Ireland (1890-91). At the end of the 1891 season he returned to England, joining West Bromwich Albion.
In 1892 he was selected for England, for whom he won 8 caps.
Bobby Evans (Wales-England)
Evans was born in Chester.He played for Chester and Wrexham before progressing to Aston Villa and Sheffield United, winning 10 Wales caps between 1906–1910.
When Evans was at Sheffield United it was revealed that he had been born in Chester,
which made him eligible to play for England, even though his parents were both Welsh.
He was selected for England 4 times (including playing in 2 victories over Wales) in 1911 and 1912.
The Oriundi
The Oriundi (Argentina-Italy)
During the Mussolini era (which in football terms was the Pozzo era) Italy relaxed their Nationality laws and went scouting for footballing talent in South America. Pozzo's 22 for the 1934 World Cup included 4 Argentinians and a Brazilian. The following represented both Italy and Argentina:
Luis Felipe Monti
The only man to play in a World Cup Final for two different countries.
Julio Libonatti
Libonatti played for Argentina 15 times (1919-1922) scoring 8 goals. In 1926 he left Newell's Old Boys to join Torino. He made his debut for Italy that year and over the next 5 years he made 17 appearances,
scoring 15 goals.
Atilio Demaría
Demaria played 3 times for Argentina in 1930-31, including 1 game in the 1930 World Cup. In 1932 he moved to Italy to play for Internazionale. He made his Italy debut that year and went on
to win 17 caps, including 1 appearance at the 1934 World Cup.
Enrique Guaita [Enrico Guaita]
First capped by Argentina in 1933,Guaita left Estudiantes to join Roma. During his time in Italy (1933–1935) he won 10 caps. appearing at the 1934 World Cup. On his return to Argentina he
resumed his international career , finishing with a total of 4 caps for Albiceleste.
Raimundo Orsi
12 caps for Argentina (1924-28), including 5 appearances at the 1928 Amsterdam Olympics. In 1929, having joined Juventus, Orsi made his debut for Italy, going on to win 35 caps in six years, including the 1934 World Cup Final. In 1936 he returned to Independente, playing one further match for Argentina.
Renato Cesarini
Having made two international appearances for Argentina 1n 1926, Cesarini was signed by Juventus in 1929. He then played 11 times for Italy in the period 1931-35. His penchant for scoring late goals gave rise to the phrase zona Cesarini in Italian football, denoting the closing minutes of a match.
Alejandro Scopelli
Scopelli was part of the famous Los Profesores line up of Estudiantes de La Plata. He joined Roma in 1933, adding 1 Italian cap to his previous 8 for Argentina. Later in his career he played in France, Portugal and Chile.
Oriundi (Uruguay-Italy)
Whilst Argentina was the happiest hunting ground for the Italians, they also looked to Uruguay.
Francisco (Francesco) Fedullo
Playing for club side Institución Fedullo made 5 (some sources say 1) appearances for Uruguay in 1928. In 1929 he received a life ban for striking a referee.The life ban was reduced to 'exile' in 1930- Fedullo could play- but not in Uruguay. He had come to the attention of Bologna in 1929 when they had visited Montevideo- and now he joined them to become the first Uruguayan to play in Italy. He scored a hattrick on his debut for Italy against Switzerland in 1932, but only played one more full international.
A World Cup winner with Uruguay in 1930, in 1934 he moved to Italy to play for Ambrosiana (Internazionale) Milan, punctuating his Uruguayan international career (12 caps), with 2 appearances for Italy in 1935-36.
Ricardo [Riccardo] Gregorio Faccio [Porta]
Faccio played 3 times for Uruguay (1932–1934). In 1933 he moved to Italy, playing for Ambrosiana (Internazionale) Milan. In 1935-36 he made 5 appearances for the Italian national side.
Amphilóquio Marques "Filó" [Anfilogino Guarisi]
Filó was the first Brazilian player to get a world cup winners medal. I'm not sure it caused much joy back in São Paulo .Having toured europe with Paulistano, Filó made his debut for Brazil in 1925. He was called up 4 times, but no São Paulo players were selected for the 1930 World Cup squad. In 1931, Filó transferred to Lazio. He played 6 games for Italy (1932-1934) , including the 1934 World Cup final.
And...
Roberto Porta did things a bit differently. He played for Italy and then Uruguay. Porta was born in Uruguay. He playedf for Nacional and then moved to Argentina to play for Independiente . In 1934 he transferred to Ambrosiana (Internazionale) Milan. Porta made one International appearance for Italy in a 2-2 draw with Hungary (Coupe Internationale européenne 24.11.35) before returning to Uruguay and rejoining Nacional. He made his debut for Uruguay in 1937 and went on to play 33 internationals, scoring 13 goals.
The Former Austro-Hungarian Empire.
Gyula Barátky [Iuliu Baratky] (Hungary- Romania)
When Gyula Barátky was born in Nagyvárad it was part of the Austria-Hungarian Empire. Whilst playing for MTK (Budapest) between 1930-1933, Barátky played 9 games for the Hungary national side.
The Miracle Blonde went on to become a popular star at Rapid București . He made his debut for Romania in 1933 and played at the 1934 and 1938 World Cups. He played 20 games for Romania, netting an impressive 14 goals.
Stefan Auer [István Avar] (Romania- Hungary)
Avar was born in Arad, Romania. He made 2 appearances for Romania in 1926-27. From 1928-35 he played for Újpest FC(Budapest), scoring 162 goals in 150 games. He made 20 appearances for Hungary betwen 1929-35, scoring 24 goals. He also played at the 1934 World Cup.
Albert Ströck [Albert Török, Adalbert Ströck] (Romania- Hungary)
Like Barátky, Ströck was born in Nagyvárad. His international career began with Romania. From 1922-26 he represented Romania 8 times,including a match at the 1924 Paris Olympics. In 1927 Ströck joined Újpest FC(Budapest) and became a feature in the Hungary national team., playing 15 internationals before he departed to play club football in Switzerland in 1932.
Mihai Tänzer [Mihály Táncos] (Romania- Hungary )
Tänzer followed a similar career path to Ströck; 10 Romanian caps including an
Olympic appearance (1922-1929), followed by 5 appearances for Hungary (1929–1932)after he had transferred to Budapest club Ferencváros.
Pavel [Pal] Teleki (Romania- Hungary)
Teleki played on international for Romania in 1927 whilst he was playing for Chinezul Timişoara. In 1931 he moved to Bocskay(now Debreceni VSC) in Hungary. From 1933-37 he appeared 8 times for Hungary, including an appearance at the 1934 World Cup.
Iuliu Alexandru [Károly] Fuhrmann (Romania-Hungary)Hungarian born Fuhrmann played one international for Romania in 1923. From 1925-1928 he played 11 times for Hungary.
Rudolf Rupec (Austria-Yugoslavia)
Rudolf Rupec was a Croatian by birth. At the time the Kingdom of Croatia-Slavonia was part of Austria-Hungary. From 1913 to 1920 he played his club football for Rapid Vienna, and won 10 caps for Austria in 1917-1918. When the Kingdom of Yugoslavia entered the international football scene in 1920 Rupec had transfered to HŠK Građanski Zagreb. He played 9 internationals for Yugoslavia, starting at the 1920 Olympics in Antwerp and finishing his international career at the Paris Olympics 4 years later.
Having represented Austria 5 times (1921-24). Having moved to DFC Prague in 1925, Kanhäuser made a surprise comeback for Czechoslovakia in 1931, playing in 2 internationals.
Prague born Vaník played for both Sparta and Slavia. In 1917 he played two games for Austria (both against Hungary)After the 1914-18 war Czechoslovakia declared its independence from the Austro-Hungarian Empire. Their first foray into international football was at the 1920 Olympics. Vaník scored a hattrick in their first game and was one of the XI who walked off the pitch in protest during the final.
Vaník played for Czechoslovakia up until 1925, his last game being against Austria. He won 12 caps and scored 10 goals.
Karel Kozeluh (Austria- Czechoslovakia)
A real all rounder. Prague born Kozeluh was European championship winning ice hockey player (Czechoslovakia) and a professional tennis champion. He was awarded 4 caps by Austria (1917-18). He played his club football with Sparta, DFC Prag and FK Teplice. Kozeluh played 2 matches for Czechoslovakia in 1923.
Sándor Nemes [Alexander Neufeld] (Hungary-Austria)
Sándor Nemes was born in Budapest. He played for Ferencváros and won 3 Hungarian caps in 1918-19. in 1919 he joined SC Hakoah Vienna. In July 1925 Hugo Meisl called up Nemes/ Neufeld for the Austrian national team. He played 2 matches for Hungary that year. Neufeld later played in the USA and Yugoslavia.
Frantisek Sedlacek [Ferenc Szedlacsek] (Czechoslovakia- Hungary)
Hungarian born, he made his debut for Czechoslovakia in 1925, playing twice. In 1928 he was selected once for the Hungary national side.
Other Europeans
Adam the Scissorsman is reputed to have invented the stepover. Born in the Dutch East Indies Adam moved to Netherlands and played for HVV Den Haag. He went to university in Zurich, joining Grasshopper and playing one international for Switzerland (versus Austria in 1929). In 1930 he was invited to play for Netherlands when they visited Switzerland, thus beginning an 11 game international career in which he scored 6 goals. Adam had to retire at 24 due to heart complaints that led to his death at the age of 32 whilst playing in a friendly match in the Dutch East Indies
Ivan Bek had a German father and a Czech mother. He didn't play for Germany or Czechoslovakia though! Born in Belgrade in the Kingdom of Yugoslavia, he played for OFK Belgrade (for whom he scored 51 goals in 50 games). Bek debuted For Yugoslavia in 1927 and participated in the Amsterdam Olympics(1928 and the 1930 World Cup (scoring 3 goals).Following a move to FC Sète (1931) Bek became a French citizen and played 5 games for France(1935–1937).
Karel Burkert (Bulgaria- Czechoslovakia)
Goalkeeper Karel Burkert was playing for Levski Sofia in Bulgaria in 1933 when he was called up to the Bulgarian national team. He played 1 international. In 1934 he returned to Czechoslovakia to play for SK Židenice (now FC Zbrojovka Brno) and was promptly selected by the Czechs (6 caps up to the outbreak of the War).
Félix (Felice) Romano (France- Italy)
Born in Argentina, Felix Romano played one game for France in 1913 at the age of 17. In 1919 Romano went to play for Torino (and later Reggiana and Genoa) in Italy. he played 5 internationals for Italy from 1921-1924.
Asia & Europe
Paulino Alcántara Riestra (Philippines-Spain)
An early star of Barcelona Alcántara represented his native Philippines before returning to Spain, where he won 5 caps, scoring 6 goals.
Flecha de Oro (Golden Arrow) was another of Los Profesores of Estudiantes de La Plata, playing 10 times for Argentina (1928-1935) In 1937 Lauri was signed by French club Sochaux-Montbéliard, and played once for France that year.
Pedro [Pierre] Duhart (Uruguay -France)
Played twice for Uruguay in 1932 whilst with Nacional. Joined Sochaux-Montbéliard in 1934, and was selected by France 6 times (1935 -37).
Marius [Eduardo] Hiller (Germany-Argentina)
South America-France.
Miguel Angel [Michel] Lauri (Argentina -France)
Flecha de Oro (Golden Arrow) was another of Los Profesores of Estudiantes de La Plata, playing 10 times for Argentina (1928-1935) In 1937 Lauri was signed by French club Sochaux-Montbéliard, and played once for France that year.
Pedro [Pierre] Duhart (Uruguay -France)
Played twice for Uruguay in 1932 whilst with Nacional. Joined Sochaux-Montbéliard in 1934, and was selected by France 6 times (1935 -37).
Europe to South America
Hiller played 3 games for Germany (1910–1911). He worked for a watch company, and in 1913 his work led to him moving to Argentina. he continued his football career, playing for CA All Boys , River Plate and Gimnasia y Esgrima de La Plata . His prolific goalscoring led to his selection for Argentina. He played 2 matches against Uruguay in 1916, scoring 4 goals in the process.
South America
Robert Sidney Buck (Uruguay-Argentina)
Almost unthinkable! 1909-1910- 3 games for Uruguay. 1912- 1 game for Argentina against Uruguay.
Delfín Benítez Cáceres (Paraguay-Argentina)
Played 15 games for Paraguay (1929-1933)- which included appearances at the 1930 World Cup. Delfín Benítez Cáceres (Paraguay-Argentina)
He moved to Argentina to play for Boca Juniors in 1932.
In 1934 he played one game for the Argentina national team.
Constantino Urbieta Sosa (Paraguay-Argentina)
Having played twice for Paraguay, Sosa became a naturalized Argentinian after moving to play club football there. He made one appearance for Argentina, at the 1934 World Cup.
Julio Lores Colán (Peru-Mexico)
Played 2 games for his Native Peru at the 1930 World Cup, then bevame the first naturalised foreigner to play for mexico, scoring 6 goals in 7 games (1935-1938)
The British Empire.
Joe Kennaway (Canada- Scotland)
The Canadian goalkeeper had made one international appearance when he was signed by Celtic in 1931. In 1933 he represented Scotland in a draw with Austria.
Gordon Hodgson (South Africa- England)
Played in one international for his native South Africa in 1924. Signed for Liverpool in 1925 and made 3 appearances for England in 1930-31.
English born Harold [Héctor] Henman played for South Africa against an Argentinian XI in 1906 and then went on to represent Argentina in one match against Uruguay, having settled there. The match in which he represented South Africa is not, however, regarded as an official full international.
And one other...
Harold [Héctor] Henman (South Africa- Argentina) 
