Arsenal U21

Early years (1887–1919)

Since Arsenal were based in Plumstead as Royal Arsenal F.C., they had a reserve side which was at first set up in 1887. The club initially played friendlies and cup competitions, winning the 1889–90 Kent Junior Cup. In 1895–96, the club which was renamed Woolwich Arsenal in 1891, had their reserves join the Kent League, winning the title the next season but leaving circa 1900. They later joined the London League where they won three titles during the 1900s.

From 1900–01 to 1902–03, the reserves played in the West Kent League, winning the league title in every season they featured within such. As they were at a level higher than their local opponents, in 1903 the team moved to South Eastern League, playing there until 1914–15 when football was suspended due to the First World War. Concurrent to this period, the reserves also entered in the London League First Division in the 1906–07, 1907–08, 1908–09, 1913–14 and 1914–15 seasons. The club went on to omit the "Woolwich" from their title in 1913, so as to be known only as "Arsenal".

The Football Combination (1919–1939)

Following the end of World War I in 1918, Arsenal Reserves took the first team's place in the London Combination league which was renamed the Football Combination in the summer of 1939. For the 1926–27 season, the competition was expanded to include teams as far afield as Portsmouth, Swansea, Southend and Leicester. During the inter-war period Arsenal's reserves matched the first team's success, winning the League South A title of 1940 and 1943 as well as being the London league champions of 1942. Additionally, from 1931 onwards the club's reserves were entered into the London Challenge Cup, winning it twice in 1933–34 and as well in 1935–36.

To give opportunities to younger players, Arsenal created an 'A' team in 1929. Initially the 'A' team entered the London Professional Mid-Week League and were champions in 1931–32. They then competed in the league until the 1933–34 footballing season. Wherein, during the summer of 1934, Arsenal had taken on Kent side Margate as their nursery team. Arsenal had agreed to send promising youngsters to Margate to give them experience in the Southern Football League and were given first choice on any Margate players. The two clubs thus enjoyed being within this relationship which had lasted for four years before Arsenal broke it off in 1938. Afterwards, Arsenal entered the reserve team in the Southern League in its own right with home games being played at Enfield F.C.'s stadium at Southbury Road. The club eventually finished in 6th place in the league season of 1938–39.

At the start of the 1939–40 season the reserves played two Football Combination games and one Southern League game before football was partly suspended due to the outbreak of the Second World War.

The Football Combination (1945–1999)

For the 1946–47 season, the Football Combination resumed but the league was split into two divisions with the winners of each division playing in a final to decide the champions. A new competition was introduced – the Football Combination Cup. This was the same teams that played in the Football Combination but divided into 4 groups with the winners of each group playing in semi-finals and a final. This format continued until the end of the 1954–55 season. From 1955–56 the Football Combination continued generally as a normal league format, occasionally consisting of two divisions with promotion and relegation. The Football Combination Cup was discontinued but re-instated for seasons 1965–66 to 1969–70 inclusive and 1996–97. The reserves continued to be entered in the London FA Challenge Cup until the 1973–74 season, with the exception of 1961–62 when the first team were entered.

The 'A' team was resurrected at the start of the 1948–49 season when a team was entered in the Eastern Counties League, Eastern Counties League Cup and East Anglian Cup, winning the Eastern Counties League in 1954–55, after which they left the league (stating that it was so strong that they needed to enter a more competitive team, which would be more expensive), but continued to play in the East Anglian Cup for the next two seasons. In addition, the 'A' team was also entered in the London Professional Mid-Week League from 1949–50 to 1957–58, winning a second time in 1952–53. During the summer of 1958, the 'A' team was entered into the Metropolitan League, Metropolitan League Cup and Metropolitan League Professional Cup. This proved a very successful venture until the mid-1960s. Towards the end of the 1960s, the 'A' team struggled against strong amateur teams and the club declined to enter a team after the close of the 1968–69 season.

1999–present

In 1999 they left the Combination to become founding members of the Premier Reserve League. They never won the competition, although they did finish as runners-up in the 2001–02 and 2010–11 seasons. At the end of the 2011–12 season they finished 3rd in Reserve League South, in what would be the competition's final season. Players from the reserve team have also been used extensively in the League Cup since the 1997–98 season. At the beginning of the 2012–13 season Arsenal's reserve and academy structure received a major overhaul. The reserve team left the Premier Reserve League and joined the Professional Development League for the competition's inaugural season. Fundamentally, replacing the reserves with an Under-21 team that has the allowance of three over-age outfield players and one goalkeeper per match day.