Olympiacos

1925–1945: Early years

Olympiacos men's water polo team was founded in 1925, being one of the first sports departments of Olympiacos CFP that was founded right after the Football team (along with the Athletics and Swimming departments).

In 1927 Olympiacos won the first League title in its history, by defeating Ethnikos Piraeus by a 3–2 scoreline in the final, with players like Nikolaos Kaloudis, Nikolaos Baltatzis - Mavrokordatos, Emmanouil Baltatzis - Mavrokordatos, Ioannis Papadakis, Andreas Athanasianos, Siadimas, Kivotos and Kordopatis.

In 1933 Olympiacos secured their second League title, after a 4–2 win against Ethnikos in the final, with players such as Andreas Kourachanis (goalkeeper), Nikolaos Baltatzis - Mavrokordatos, Takis Provatopoulos, Ioannis Papadakis, Ioannis Isigonis, Andreas Athanasianos and Kivotos. Provatopoulos scored 3 goals and Athanasianos one.

The next season the Red-Whites won a back-to-back League title, by defeating Ethnikos once again with the same 4–2 scoreline in the final. The goals were scored by Provatopoulos (2 goals), Leonidas Alexiou and Isigonis.

In 1936 the team secured their fourth Greek Water Polo League title, this time by defeating K.O. Piraeus with 5–1 in the final.

On 28 October 1940, Fascist Italy invaded Greece, and several Olympiacos players joined the Hellenic Armed Forces to fight against the Axis invaders in World War II. Olympiacos water polo goalkeeper and swimming champion Andreas Kourachanis, was killed in a battle against the Italians. Hellenic Navy Ensign Takis Kontaratos, who was both an Olympiacos water polo player and a midfielder of Olympiacos F.C. as well, was one of the 72 Greek soldiers who were killed in the sinking of Greek destroyer Vasilissa Olga by Junkers Ju 88 bombers of LG 1 of Nazi Germany's Luftwaffe in Lakki harbor of Leros on the morning of 26 September 1943.

1946–1992

After the war, Olympiacos created a very strong team that won 4 Greek League titles from 1947 to 1952 (1947, 1949, 1951, 1952). The 1949 title was won by players like Takis Provatopoulos, Alekos Monastiriotis, Manolis Papadopoulos, Leonidas Alexiou, Christos Oikonomou, Asimakis, Kleoudis, Maragoudakis, Dimitropoulos and Chalas, after a 3–1 win against Ethnikos Piraeus. In 1951 under the guidance of coach Christos Svolopoulos and players like Takis Provatopoulos, Alekos Monastiriotis, Manolis Papadopoulos, Nikos Teleionis, Babis Gerakarakis, Vasilis Ontrias and Asimakis secured the Greek League title after a 6–2 against N.O Mitilinis in the final. The next season, they won their 4th title in 6 years with key players such as Alekos Monastiriotis, Leonidas Alexiou, Nikos Teleionis, Babis Gerakarakis, Nikos Bistis, Vasilis Ontrias and Asimakis.

In 1969, after a 17-year drought, Olympiacos was crowned Greek champions again, under the guidance of coach Makis Charitos and players like Ioannis Palios, Takis Michalos, Periklis Damaskos, Georgios Palikaris, Stathis Sarantos, Vangelis Koskinas, Spyros Tsiminos, Giorgos Venardos, Spyros Ioannidis, Ilias Damaskos and Omiros Polychronopoulos.

In 1971, Olympiacos board hired the world-class head coach Ivo Trumbić (Hall of Fame inductee in 2014), under whose guidance Olympiacos won the League title in 1971, the 10th Greek League title in the club's history, with a roster of solid Greek players like Ioannis Palios, Takis Michalos, Periklis Damaskos, Georgios Palikaris, Stathis Sarantos, Vangelis Koskinas, Giorgos Venardos, Spyros Ioannidis, Sarantis Sarantos, Ilias Damaskos and Omiros Polychronopoulos.

After the 1971 title, Olympiacos created several strong teams in the following years, like the 1979 team coached by Mile Nakić with players like Stathis Sarantos, Spyros Kapralos, Andreas Gounas, Giorgos Venardos, Spyros Tsiminos, Babis Charalambidis, Nikos Beristianos, Christos Daras and Antonis Karavanos. and later on with solid Greek players like Michalis Kouretas, Giorgos Katsoulis, Giannis Ladas, Andreas Miralis, Giorgos Michailidis, Thanasis Katsoulis and Manolis Psarros but nevertheless, the Red-Whites spent twenty-one years without a League title.

1992–2019: The Golden Era

Domestic domination, first European final (1992–1998)

In 1992 Olympiacos finally returns to the top of Greek water polo in an impressive fashion, winning both the Greek League and the Greek Cup to complete the first Double in its history. Under the guidance of coach Nikos Loukatos and players like Kyriakos Giannopoulos, Nikos Venetopoulos, Antonis Aronis, Thodoris Vlachos, Kostas Loudis, Dimitris Kravaritis, Themis Chatzis, Sakis Platanitis, Charis Pavlidis και Zafeiris Tzinis, Olympiacos clinched their history's eleventh Greek League title and their first ever Greek Cup after a 9–8 win against NO Patras in the final.

The next season Olympiacos hired Boris Popov, one of the world's greatest water polo coaches, who was head coach of the Soviet Union men's national water polo team that remained undefeated from 1980 to 1986 and won the gold medal at the 1980 Olympics and the gold medal at the 1982 World Championship. Under Popov's guidance, the Red-Whites won a second consecutive domestic Double, securing their history's 12th League title, as well as the Greek Cup after an 8–4 win against ANO Glyfada in the final.

The next three seasons (1994–95, 1995–96 and 1996–97), Mile Nakić came back for a third successful stint in Olympiacos and coached the Red-Whites to two consecutive Greek League titles (1994–95, 1995–96), beating Ethnikos Piraeus in 1995 (3–0 wins in the finals) and NO Vouliagmeni in 1996 (2–1 wins in the finals) and one Greek Cup (1996–97), beating NO Patras 9–8 in the Cup final. Key players of this Olympiacos team were Thodoris Chatzitheodorou, Nikos Venetopoulos, Kostas Loudis, Makis Voltirakis, Themis Chatzis, Sakis Platanitis, Thodoris Vlachos, Dimitris Kravaritis and Charis Pavlidis.

In season 1997–98, Nikos Loukatos, the coach of the 1992 Double, was hired as head coach and players like Giannis Thomakos, Antonis Vlontakis and Gavin Arroyo joined the team. Under Loukatos guidance, the Red-Whites won the Greek Cup after a 10–8 win against NO Patras in the final and the Greek Super Cup, beating Vouliagmeni 10−5 in the final. Most importantly, Olympiacos reached a European final for the first time in its history; after an impressive campaign, the team qualified for the LEN Cup Winners' Cup two-legged final, where they played against Ferencváros. Olympiacos won the first leg in Piraeus by 7−6, but lost the second leg 8−6 in Budapest after a thrilling game.

European powerhouse: twice European champions, Super Cup champions, twice Quadruple winners, domestic dynasty (1998–present)

From 1998 to 2005 Olympiacos won 7 consecutive Greek League titles which is a record for the A1 League, which was established in 1987, and a record as well for the club.

In season 1998–99 Nikola Stamenić, one of the greatest coaches in the history of the sport, became the team's new head coach. Under Stamenić guidance, Yugoslavia men's national water polo team had won the gold medal in both the 1991 World Championship in Perth and the 1991 European Championship in Athens, becoming World and European Champions in the same year. Stamenić imposed strict professional conditions in Olympiacos, establishing a very demanding training program, iron-fisted discipline and meticulous tactical analysis.

Under Stamenić, Olympiacos players improved significantly in both mental, physical, technical and tactical level, and in two years they managed to win 2 Greek League titles, 1 Greek Super Cup, and reach the final of the LEN Cup Winners' Cup in 1999, where they lost to Mladost, despite coming close to an amazing come-back in the second final leg, where they led the score by 10−2 at some point in the game (10−6 final score). Stamenic became a legend for the club and his contribution to Olympiacos and to Greek water polo in general is considered enormous. His training methods, his tactics and his deep understanding of every aspect of the game of water polo exerted a great influence on this generation of Olympiacos players.

Stamenić left Olympiacos in the summer of 2000 and Dragan Matutinović became the team's new head coach. Olympiacos had a very successful season, winning both the Greek League and the Greek Cup and becoming the first ever Greek club to reach the LEN Champions League final. In the semi-final of the LEN Champions League 2000-01 Final Four in Dubrovnik, they beat Italian powerhouse CN Posillipo with 7–6 and reached the final of the competition. There, they faced home team VK Jug and lost 8–7 after two overtimes in a thrilling game which was marked by a highly controversial decision of referee Boris Margeta. With the score at 5–5, Olympiacos scored a goal with a spectacular backhand shot by Thodoris Chatzitheodorou with only 4 seconds left in the game, a goal that was disallowed by Margeta as a foul.

Despite the great season, Matutinović left the club and Olympiacos board signed the great Hungarian coach Zoltán Kásás to replace him. Under Kásás guidance in 2001–02 Olympiacos had the most successful season in their history. They became the first club ever in water polo history (since the establishment of the modern Champions League format in 1996) to win four out of four competitions in a single year, thus completing the Continental Quadruple, comprising the Triple Crown (LEN Champions League, Greek Championship, Greek Cup) and the LEN Super Cup. They won both the 2002 LEN Champions League and the 2002 LEN Super Cup in Budapest, beating home teams Honvéd and Vasas respectively. Key players of this historical Olympiacos team were Makis Voltirakis, Thodoris Chatzitheodorou, Petar Trbojević, Giannis Thomakos, Themis Chatzis, Antonis Vlontakis, Giorgos Psychos, Thodoris Kalakonas, Nikos Deligiannis, Sakis Platanitis, Dimitris Kravaritis and Arsenis Maroulis.

In season 2002–03 with Kásás as head coach Olympiacos went on to win the Greek League and the Greek Cup and the next two seasons (2003–04 and 2004–05) under Veselin Đuho's guidance the club managed to win 7 consecutive Greek League titles, an all-time record.

From 2006 to 2011 Olympiacos under the guidance of Greek coach Vangelis Pateros, won 5 consecutive domestic Doubles, two of which (Greek League and Greek Cup 2009, Greek League and Greek Cup 2010) undefeated and with 31 wins in 31 matches in both seasons, completing 11 Greek League titles in 12 seasons. In European competitions, they reached 2006–07 LEN Euroleague Final Four in Milan, where they lost 10–9 to eventual European Champions Pro Recco in a thrilling semi-final that was decided in the last seconds of the game.

In 2011, Thodoris Vlachos (who had a long and successful career in Olympiacos as a player) became the new head coach of the team. From 2011 to 2019 under the guidance of Vlachos, Olympiacos have won 1 LEN Champions League, 7 Greek League titles, 6 Greek Cups, 1 Greek Super Cup, 1 Continental Quadruple, and 6 domestic Doubles. In 2018, they won the 2017–18 LEN Champions League in Genoa, beating once again a home team in the final, the Italian powerhouse Pro Recco, the most successful club in the competition with 8 titles. Olympiacos dominated the final game and won the title with a 9–7 scoreline against the Italian side inside their home ground. Along with their second LEN Champions League title, they also completed the second Quadruple Crown in their history (LEN Champions League, Greek Championship, Greek Cup, Greek Super Cup). Key players of this Olympiacos team that was crowned European Champion for the second time in the club's history were Josip Pavić, Giannis Fountoulis, Andro Bušlje, Konstantinos Genidounias, Manolis Mylonakis, Paulo Obradović, Konstantinos Mourikis, Vangelis Delakas, Giorgos Dervisis, Alexandros Gounas, Stelios Argyropoulos and Dimitris Nikolaidis. Under Vlachos, Olympiacos have also reached the final of the 2015–16 LEN Champions League in Budapest, where they lost 6–4 to VK Jug, and the final of the 2018–19 LEN Champions League in Hannover, where they lost in the penalty shootout to Ferencváros.

Overall, from 2006–07 through the 2022–23 season, Olympiacos domestically won 15 Doubles (Greek Championship and Greek Cup) in 17 seasons, five of them straight (2007–2011), and six more undefeated and having won every game (without even a single draw) in both the Greek League and the Greek Cup (2008–09, 2009–10, 2013–14, 2014–15, 2015–16, 2017–18). The club also holds many more unique records in the domestic competitions. They have achieved an all-time record of 163 straight wins in both the Greek League's regular season and play-offs, which lasted from May 2013 to May 2019. Additionally, Olympiacos holds the record for the fewest losses (overall), the most goals scored in a season (446 goals in season 2017–18, beating their previous record of 444 goals in season 2015–16), and the fewest goals conceded in a season (100 goals in season 2015–16).