"Kimi no Heart wa Marine Blue" (Japanese: 君のハートはマリンブルー, Hepburn: Kimi no Hāto wa Marinburū) is a single by Japanese band S. Kiyotaka & Omega Tribe released by VAP on January 21, 1984.

[2] After the poor sales of the band's previous single, "Asphalt Lady", the production team refocused their efforts on better compositions for future songs including "Kimi no Heart wa Marine Blue".

Fujita composed a "sorrowful sound" as well as leaning into the image of the sea that was present in their debut single, "Summer Suspicion".

[3] While recording, Fujita made vocalist Kiyotaka Sugiyama do multiple takes and gave detailed criticisms for every vocal take, telling Sugiyama to "paint a picture" in his head and "be the hero of the story" while singing.

[1] The song made its debut on the Fuji TV show Yoru no Hit Studio (夜のヒットスタジオ) on April 9, 1984.