The franchise was slow to replicate its initial success: the Orions made the Japan Series in 1960 and 1970, only to lose both years.

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.

This eventually caused their attendance there to crash, going from sold-out games in 1973, to only about 2,000–3,000 attendees for their last few years in Sendai.

[3] 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.

[4] 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.

The current logo's design features a baseball in the background with a seagull soaring, with the club's name around the circle.

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 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.

The Marines would edge out the Hawks and Eagles in a close playoff race in 2023, finishing 2nd with a 70-68-5 record.

That season would be the last for ZOZO Marine Stadium public address announcer Emi Taniho.

Alongside the team's mascots Mar-kun, Rine-chan and Zu-chan, they entertain the crowd during Marines games, with 27 members.

With his girlfriend Rine-chan (リーンちゃん, Riin-chan) and his young brother Zu-chan (ズーちゃん, Zuu-chan), he entertains spectators at team games.

Originally Rine-chan wore a pink sports visor cap till the 2022 season when she wore the same baseball cap as her boyfriend while retaining the skirt, while Zu-chan wears the cap backwards and wears an apron instead of the jersey beginning 2022, before that he wore a shirt unless all three wear their team's special home uniforms.

[12] Back when the team were known as the "Lotte Orions", their mascot was a character known simply as Bubble-Boy (バブル坊や, Bable-Boya) who only appeared as a logo.