[1] In 1924, West Ham were the first club to visit Germany following the culmination of World War I, playing Köln, Waldhof Mannheim, Borussia Mönchengladbach, Eintracht Frankfurt and Freiburger FC.

In the opening game on 23 September 1964, West Ham won 1–0 in Belgium thanks to a headed Ronnie Boyce goal from an Alan Sealey corner.

In the home leg, West Ham fans paid record match receipts to see what was described as a "decrepit performance which brought jeers from the crowd".

[7][8][6] Manager Greenwood, in his 1984 book Yours Sincerely, noted the significant roles played by Sealey, Dear and Bobby Moore in the final but also praised West Ham's defence, particularly the efforts of goalkeeper Jim Standen and defender Jack Burkett.

In a game refereed by future 1966 FIFA World Cup Final linesman Tofiq Bahramov, Martin Peters scored twice for West Ham with an own goal by Eddie Bovington and an 80th penalty by Kostas Polychroniou for Olympiakos.

Lahden Reipas took the lead in the fourth minute through Harri Lindholm after his shot had hit West Ham goalkeeper Mervyn Day in the chest and gone in.

[23] In the return leg in London, West Ham ran out 3–0 winners thanks to goals from Keith Robson, Pat Holland and Billy Jennings.

Goals for Billy Bonds, Paul Goddard, a Ray Stewart penalty and another for David Cross gave them a strong lead ahead of the away leg.

[38] Following the defeat, West Ham manager John Lyall praised Dinamo Tbilisi, saying "If we are eliminated from the competition, I will at least be happy that we lost to such a high class team".

[33] Following their fifth-place finish in the previous season's Premier League,[45] West Ham, now managed by Harry Redknapp, entered the UEFA Intertoto Cup.

[46] In Finland, Jokerit took the lead through Tero Koskela before Frank Lampard Jr. equalized in the 70th minute with a 20-yard free-kick to put West Ham into the next round.

[60] In the second round, West Ham faced Romanian team Steaua București, going down 2–0 in the first-leg, following goals from Laurențiu Roșu and Sabin Ilie.

[71][72] Manager Alan Pardew gave full debuts to recent signings and Argentine internationals Javier Mascherano and Carlos Tevez in the games.

[78] The second leg, on 9 July, was moved to the 1,300 capacity Estadi Comunal d'Andorra la Vella with West Ham supporters receiving a ticket allocation of 450.

With Manchester United having already secured a place in the competition's group stage with a fifth-placed finish in the 2015–16 Premier League, their cup winners' slot passed to West Ham in seventh.

[96] The away leg was switched from Domžale's Sports Park ground, to the 16,038 capacity Stožice Stadium in Ljubljana, home of the Slovenia national team.

West Ham won 3–0 with two goals from Cheikhou Kouyaté and a third from Sofiane Feghouli, resulting in a 4–2 aggregate victory to progress to the play-off round.

Playing the away leg in Genk, Joseph Paintsil scored for the Belgians in the 4th minute before two goals by Saïd Benrahma put West Ham in the lead.

[111] Following crowd disturbances in this game West Ham were banned from selling tickets to their supporters for the away fixture by UEFA, against Rapid Vienna on 25 November.

[123] West Ham lost the first leg of the semi-final, played on 28 April at the London Stadium, Frankfurt scored inside the first minute with a goal by Ansgar Knauff.

FCSB's Andrei Cordea scored in the first-half but second-half goals from Jarrod Bowen, a penalty, Emerson, his first for the club, and Michail Antonio put West Ham top of Group B after the first round of matches.

[141] On 3 November, West Ham became the first side to progress from the UEFA Europa Conference League group stage with a 100% record as they beat FCSB 3–0 in Bucharest.

[147][148] The first leg, played on 13 April, in Belgium finished 1–1; West Ham scored just before half-time with a tap-in by Danny Ings from a cross by Jarrod Bowen.

[149][150] The second leg of the quarter-finals was at home in the London Stadium on 20 April; West Ham won 4–1, resulting in an aggregate score of 5–2 earning a place in the Europa Conference Semi-finals.

[162] In July 2023, UEFA fined Alkmaar £68,670, £6,115 for throwing objects, £12,870 for lighting fireworks, £6,867 for blocking public passageways and £42,918 for crowd disturbances and failure to ensure that spectators could not move from one sector to another.

[163] West Ham were paired against Italian team, Fiorentina in the final to take place at the Fortuna Arena in Prague, Czech Republic on 7 June 2023.

The game remained goalless until referee Carlos del Cerro Grande awarded the Hammers a penalty in the second half after the ball hit the hand of Fiorentina captain Cristiano Biraghi after a long throw into the box.

[172] On 8 June thousands lined a route from the Champions Statue to Stratford Town Hall as West Ham players took part in an open top bus parade to show the trophy and celebrate the win.

A defensive error by Angelo Ogbonna in the 47th minute allowed Petar Stanić to rob him of possession before running on to score past Łukasz Fabiański.

Nayef Aguerd headed in a James Ward-Prowse corner past goalkeeper Noah Atubolu to make it 2–1 to West Ham, the final score.