Doraemon The Movie: Nobita's Great Battle of the Mermaid King (2010)

In this animated adventure, Nobita and friends use Doraemon's gadgets to explore the ocean's depths, discovering a beautiful underwater kingdom. Their amazement turns to action as they learn of a looming threat from a mermaid kingdom's foes. Together, they embark on a daring mission to save the aquatic realm, facing challenges that test their bravery and bonds. A must-watch for its stunning visuals and heartwarming message of friendship and courage.