|"I've had forty years to develop this plan, brother."
Season 15: Seabound is based on an upcoming release.
This fifteenth season of LEGO Ninjago, subtitled Seabound, is preceded by Season 14. It will air in the second half of 2021, the same year as the series' 10th anniversary. Nya is the focus character.
- Cole - Kirby Morrow
- Jay - Michael Adamthwaite
- Kai - Vincent Tong
- Lloyd Garmadon - Sam Vincent
- Nya - Kelly Metzger
- Zane - Brent Miller
- 71750 Lloyd's Hydro Mech
- 71752 Ninja Sub Speeder
- 71754 Water Dragon
- 71755 Temple of Endless Sea
- 71756 Hydro Bounty
- This season's name, Seabound, sounds very similar to the name of Season 6, Skybound. Nya is one of the main focus characters in both seasons.
- On September 9, 2020, Tommy Andreasen said that depending on how this season turns out, it may be his favorite.
- The 2021 storyline will focus on Nya and her elemental powers.
- On January 14, 2021, the Ninjago's 10th anniversary, Tommy Andreasen said that they had received the render of the last episode of 2021 from WildBrain, and had done the first voice record for the 2022 episodes the day before.
- Although Kirby Morrow unexpectedly passed away in November 18, 2020, it is confirmed that he recorded Cole's lines for this season prior to his death. LEGO announced that the 2021 episodes will be dedicated to his honor.
- On February 13, 2021, Tommy Andreasen tweeted "Reviewing final sound mix and colour grading on the last of the 2021 episodes today. It is not an easy watch for several reasons..."
- When asked if Cole will be retired from the show following the season's conclusion, Tommy replied that they "have considered every possibility and it was not a task we took lightly."