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This page contains major spoilers that have not yet appeared in any episodes anywhere worldwide.
|“||Try to survive season 2, because it'll be nothing compared to season 3.||”|
The third season of Miraculous: Tales of Ladybug & Cat Noir was confirmed to be in progress by Jeremy Zag. It will have 26 episodes. According to Thomas Astruc, episodes in this season will be self-contained, but there will be powerful ongoing story arcs. The season is expected to premiere in Early 2019..
For Ladybug and Cat Noir, despite their new powers and teammates that they can call upon when the situation requires it, the fight with Hawk Moth becomes harder and harder. Their opponent is always stronger as long as he can call on Mayura, a villain who can create allies for the Akumatized, the supervillains.
More powers, more action, more villains, and more emotions! Season 3 will put Adrien and Marinette to the test: Will they be able to keep their secret and prevent their private life from interfering with their superhero adventures?
On July 3, 2016, Thomas Astruc explained that Season 3 is being written at the same time as Season 2, in order to prevent a hiatus between seasons.  As of January 14, 2017, the season is still in the writing process.
At a panel at New York Comic Con on October 7, the crew revealed a new sneak peek image of Le Paon, with the image labeled as being for Season 3. They also showed concept art of Duusu, whose image noted her as appearing in both Season 2 and Season 3. In a teaser for a Los Angeles Comic-Con panel for October 30, Jeremy Zag revealed that a fan of the show will be akumatized in Season 3.
Astruc confirmed at Comic Con Paris on October 23 that the crew is currently writing Season 3, and because they set the bar very high for Season 2, the writers have a lot of pressure to improve from that with Season 3.
On March 1, 2017, Astruc announced on Twitter that the crew had written three episodes in one day, saying that "on the menu" are a "big party, apocalypse, and DBMAT." The next day, he added a picture of what DBMAT stood for, Dragon Ball Martial Arts Tournament from the franchise Dragon Ball. Later that month, on March 22, director Wilfried Pain revealed that the production of the season was in its storyboarding and animatic phases.
When asked on April 10, 2017, if the show will include new heroes that are more diverse, the official Miraculous Ladybug Tumblr blog replied that it would, noting, "Wait until you see Season 3!" In response to a user asking about his day, Astruc posted that the crew had finished writing another episode that "will blow [their] mind" and only had six more episodes left to be written for Season 3.
On Twitter on May 1, 2017, Astruc posted that he was working on finishing a story before the next day, noting that in it, Marinette and Adrien will be together, with Astruc calling it "EXTREME Adrienetting." On May 17, during a live event for the series, Princess Fragrance was confirmed to return for the season, along with other akumatized villains in a huge event.
At Dokomi 2017 on June 4, Astruc and Pain revealed that in a week, the crew will be creating the Season 3 finale.
In a press release video from TFOU on August 31, 2017, new information surfaced about a two-part special previously teased in May, "Heroes' Day", with "the best of the worst akumatized villains" returning and fighting the superheroes.
On December 28, 2017, in an interview, Pain noted that there is an episode in Season 3 that involves theater, and it will include a game that has references to anime.
On March 20, 2018, Pain shared a rough animation of a Season 3 episode under the production code LB317. On May 6, 2018, a poster of the third season's poster was shown at the CONQUE event in Mexico. During the Japan Expo 2018 panel on July 9, 2018, Sébastien Thibaudeau revealed that the 78th episode had moved the team to tears. He hoped this would have the same effect on the spectators. On July 17, 2018, Morade Rahni, a storyboard designer, posted on Twitter an animatic of Rena Rouge detransforming. He also tagged the image with #Season3.
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- Astruc's intention for Season 3 is to find out why Hawk Moth wants the Miraculouses.
- The Season 1 Origins episodes would suggest that, quoted by Nooroo, if both Miraculouses are obtained by one person, "ultimate power will be achieved."
- According to Feri González in Season 3 there will be a lot of references to Season 2.