The franchise began in 1950 as the
Mainichi Orions, an inaugural member of the
Pacific League, and were owned by the
Mainichi Shimbun newspaper. The Orions were named after
the constellation of the same name. The Marines won the inaugural
Japan Series in
1950. In 1958, the team was merged with the
Daiei Unions and renamed the
Daimai Orions, to reflect that both Daiei and Mainichi had a 50% stake in the team, with control being given to
Daiei Film president
Masaichi Nagata. In 1964 they became the
Tokyo Orions, and then the
Lotte Orions in 1969. The franchise was slow to replicate its initial success: the Orions made the
Japan Series in 1960 and
1970, only to lose both years. The team played in
central Tokyo until 1972. From 1973 to 1977 the
Lotte Orions played in the northern Japanese city of
Sendai. In
1974, they beat the
Chunichi Dragons, becoming the first Pacific League team to win the Series in ten years, as the
Yomiuri Giants had claimed the prior nine titles behind the
Oh–
Nagashima attack. After beating the Dragons, their owners, Lotte Holdings, decided to hold their victory parade in Tokyo, which surprised fans in Sendai. This eventually caused their attendance there to dwindle, going from sold-out games in 1973, to only about 2,000–3,000 attendees for their last few years in Sendai. In 1977, the Orions signed
Major League Baseball player
Leron Lee, who ended up playing for the team for eleven seasons, compiling a .320 career batting average and slugging 283 home runs with 912 career RBI. From his retirement to early 2018 (when surpassed by
Norichika Aoki), Lee held the Japanese record for career batting average (players with more than 4,000
at bats). In 1978, Lee invited younger brother
Leon Lee to play in Japan, and the brothers formed a feared cleanup for the Orions for five seasons — in 1980, Leron had 33 home runs, 90 RBI, and a batting average of .358; while Leon slugged 41 home runs and drove in 116 runs, with a batting average of .340. In 1978 the team returned to the Tokyo area, settling in the
Kawasaki Stadium, at one time home to the
Taiyo Whales (now
Yokohama DeNA Baystars). In 1992, the team moved to
Chiba City's
Chiba Marine Stadium on the eastern shore of
Tokyo Bay. They held a fan vote for a new name for the team; the name "Dolphins" won, while another popular choice was "Pirates". However, the name "Dolphins" was thrown out because though an unrelated team named the
Nagoya Golden Dolphins (later known as
Nagoya Kinko) was long defunct, the letter "D" in broadcasts was already taken by the Dragons; while "Pirates" was disregarded because the Chiba Pirates name was used by a team in . Executives didn't want the team to be associated by a team that they think was supposed to be awful, supported by the fact that by then the Orions had finished their 6th consecutive losing season, finishing in 6th in three of the last four seasons, alongside the fact that they were unsure if they could even use it to begin with, due to
Japanese copyright laws. "Marines" was ultimately chosen because the team believed it meant "heroes of the sea" (and because the letter "M" was available), yielding the current club name
Chiba Lotte Marines. Originally, the club used pink, blue, and white on their logo, which included a pirate ship, with a seagull below it, and a wave pattern to reflect the ocean currents off Chiba's coast. In 1995, this was changed to the logo's current design, while dropping pink and blue in favor of red, black and white (with red being dropped in 2019). The current logo's design features a baseball in the background with a seagull soaring, with the club's name around the circle. The team failed to reach the
Japan Series again
until 2005. The Marines started the
2005 season in first place behind American manager
Bobby Valentine, who had returned after having managed the team to a 2nd place finish
in 1995 behind the
Orix BlueWave, but struggles between him and general manager
Tatsuro Hirooka which had him leave after the lone season, but fell behind the
Fukuoka SoftBank Hawks as the year progressed. Under the playoff format of the time, the preliminary five-game playoff round, prior to the Japan Series, saw the teams with the best first and second half records face off. The Marines defeated the Hawks three games to two in the
Pacific League championship, winning the rubber match despite entering the eighth inning trailing, 2–1. The Marines were thus qualified for the
Japan Series, the first time they had reached the tournament since 1974, after 31 years. In a one-sided series, the Marines swept the
Hanshin Tigers in four games, scoring ten runs in each of the first three games. The apparent ease with which the Marines defeated the Tigers added fuel to the ongoing debate concerning the need for a
playoff system in the
Central League, which was finally added in 2007 (see
Climax Series). The Marines went on to defeat South Korea's
Samsung Lions in the final round of the
Konami Cup Championships.
In 2010, the Marines clinched third place on the last day of the season to earn a berth into the Climax Series. They went on to become the first third place team to ever win the Climax Series, and faced off with the
Chunichi Dragons in the
2010 Japan Series. The Marines defeated the Dragons in seven games, composed of four wins, two losses, and one tie, winning their second Japan Series in under ten years.
In 2013, the Marines clinched third place to clinch a berth in the Climax Series and faced the
Saitama Seibu Lions in the first stage. They defeated the Lions in 3 games to move onto the final stage. They would lose to the
Tohoku Rakuten Golden Eagles in 5 games, who would go on and defeat the
Yomiuri Giants in 7 games to win their first (and still only) Japan Series title. They would make it back in the playoffs in 2015. They defeated the
Hokkaido Nippon-Ham Fighters in 3 games in the first round, then got swept by the
Fukuoka SoftBank Hawks, who received a one-game advantage for having the best record in the Pacific League. The following season, they returned to the playoffs. They would make a much earlier exit, as they were swept by the Hawks in two games in the first stage. It would not be until 2020 when they returned to the playoffs. The
Hawks, with a one-game advantage, would sweep them again in the first stage. They bounced back the following year by defeating the
Eagles in 2 games in the first stage, including a tie in the second game which allowed them to advance as they had the better record at 67-57-19, while the Eagles had a 66-62-15 record. They got swept by the
Orix Buffaloes in the final stage in 3 games, however a tie in the third game and Orix having the better record at 70-55-18, allowed the Buffaloes to advance. On April 10, 2022,
Rōki Sasaki threw a
perfect game,
Nippon Professional Baseball's first in 28 years and the 16th in the league's history. Sasaki tied an existing record by
striking out 19 batters, and setting a new record by striking out 13 consecutive batters. It didn't do much to help the season, as the Marines finished in 5th place with a 69-73-1 record, and
Tadahito Iguchi would be let go after that season, replaced by
Masato Yoshii. The Marines would edge out the Hawks and Eagles in a close playoff race in 2023, finishing 2nd with a 70-68-5 record. They would defeat the Hawks in 3 games in the first stage, but lost in 5 games to the
Buffaloes in the final stage, who also had a 1-win advantage for having the best record in Pacific League. The season would be the last for
ZOZO Marine Stadium public address announcer . Originally, she was given a farewell ceremony on October 7, 2023, supposedly her last home game, which included many former Marines players, but she was given extended duty, as the Marines were appearing to make a run for the
Climax Series. The game was also her 2,100th game announcing. Her actual last day with the team was on December 20. ==Current roster==