In 1980s Mode, the main character is Ryoba Aishi, Yandere-chan's mother, who is the yandere girl featured in the Mysterious Tapes. Her appearance will resemble the Yandere-chan from the save file that was used to start 1980s Mode.
This mode will only have technology that was available in 1989, along with stricter school rules. There will be no Internet, smartphones, Info-chan, or anything else that did not exist prior to 1989. The smartphone will be replaced with a notepad. There will be an optional filter that will make the game look grainier and older, to help represent the fact that this mode takes place in the past. The Basement Tapes are the epilogue of 1980s Mode.
The objective of this mode will be to defeat ten rivals, like in Story Mode. Ryoba will have to stalk her senpai to figure out who the rival of the week is instead of finding it out from Info-chan. However, the plot of 1980s Mode will most likely not be as elaborate as Story Mode. YandereDev does not want the inclusion of this mode to delay the game, so he would prefer for this mode to be simple enough to be created within a month's time.
- This mode will not be included in the free demo.
- Before the events of 1980s Mode, there was a murder at Akademi High which prompted the school to force faculty members to undergo self-defense training before the player starts 1980s Mode.
- The idea for 1980s Mode occurred when someone complained that they did not like Info-chan and wanted a mode without her.
- YandereDev would like help from volunteers to make period-correct outfits and hairstyles for the 1980s.
- This mode will also feature a brand new student body with a different configuration of colors and accessories.
- The Info Club room may be an 'Investigative Journalism" club in this mode.
- It is possible that The Journalist may appear in the ending cutscene of this mode.
- Senpai's parents may not appear in this mode.
- The events of 2019 are partially determined by the events of 1989, so there will be a "canon" way to eliminate each rival. If the player chooses to go with the canon elimination methods, then the Mysterious Tapes are proven true.
- This mode will feature the death of the Phantom Girl.
- She may be killed in the introduction sequence to avoid a time paradox. 
- This mode will feature the previous Delinquents,  and may feature Horuda Puresu. It may also possibly feature the removed rainbow students. YandereDev said that if the framerate is more stable enough and there is more room for more students, then the rainbow students will be in Story Mode, and if not, then they'll appear in this mode. 
- This mode is meant to be the most difficult mode. It may include the player getting a Game Over if a witness escapes, since in the Mysterious Tapes, the yandere of 1989 was arrested with no hard evidence.
- YandereDev has stated that he will attempt to give this mode the same vibe as "a peaceful countryside Japanese town in the late 80s".
- This mode may only be nine weeks long, or Ryoba will spend the tenth week romancing her senpai.
- The tenth week would possibly involve getting incriminating evidence against the Journalist.
- The outcome of this mode will not effect the story.
- Genka Kunahito's mother will appear in this mode.