It stars the voices of Jacob Tremblay, Jack Dylan Grazer, Emma Berman, Saverio Raimondo, Marco Barricelli, Maya Rudolph, Jim Gaffigan, Peter Sohn, Lorenzo Crisci, Marina Massironi, and Sandy Martin in supporting roles.

The film is set on the Italian Riviera in 1959, and centers on Luca Paguro (Tremblay), a young sea monster boy with the ability to assume human form while on land, who explores the town of Portorosso with his new best friends, Alberto Scorfano (Grazer) and Giulia Marcovaldo (Berman), experiencing a life-changing summer adventure.

The boys run afoul of Ercole Visconti, the local bully and five-time champion of the Portorosso Cup, a triathlon of swimming, pasta-eating, and biking.

On July 30, 2020, Pixar announced a new film titled Luca as an "Italy-set coming-of-age story", with Enrico Casarosa directing and Andrea Warren producing.

Some design details that carried through to the final film are things like the shapes of the fins of the sea monsters, how decorative their scales are, and the curves of their tails.

To create the setting of the movie, Portorosso, the studio sent several of the film's artists to the Italian Riviera for a research trip, including on the Cinque Terre, during which they took photos of the area's landscape and peoples.

During the research trip, Deanna Marsigliese, the film's art director, noted that they were watched by curious onlookers and chose to incorporate that into the character designs.

[31] Animation supervisor Mike Venturini stated: "Enrico, as a director and as an artist, was inspired in his youth largely by Miyazaki's film library, starting with one of his first projects ... Future Boy Conan.

In addition of Miyazaki's works, Casarosa stated that Aardman and Anderson's stop-motion movies also influenced his artistic sensibilities: "Some of that ends up in my drawings, that sketchy and expressive style.

"[35] Casarosa and the team began testing new animation concepts, hoping to bring playful silliness to the characters by taking away some of the typically large amount of detail.

Areas of immediate focus were using a more 2D pose style, wider mouths with rounded, rather than angled corners, and multi-limb motions that brought a sillier feel to character movement.

[42] It is the first Pixar film to involve Andrews, while Jones had previously co-written Soul (2020) and is also credited as a Senior Story and Creative Artist at the studio.

"[44] On February 25, 2021, with the release of the teaser trailer and poster, Tremblay, Grazer, Berman, Rudolph, Barricelli, Raimondo (it) and Gaffigan were announced as part of the cast.

"[45] Casarosa stated that Grazer, who voiced Alberto, brings "a natural confidence and vulnerability" to the character, "who's a free-spirited teen sea monster with unbridled enthusiasm for the human world."

Rudolph and Gaffigan, playing Daniela and Lorenzo, did get the chance to improvise, with Casarosa highlighting the depth and warmth they bring to the roles: "She's a stern mother.

Raimondo compared Ercole to the character Odd Henderson from the short story The Thanksgiving Visitor, and voicing him he was inspired by Giuseppe Anatrelli's performance as Luciano Calboni from the Fantozzi film series.

"[18][45] Casarosa stated that the movie is a celebration of friendship, and "a love letter to the summers of our youth – those formative years when you're finding yourself",[39] inspired by his childhood in Genoa.

"[49] He has welcomed the interpretation after the film's release, also stating: "While I identify with pronouns he/him and I am a straight man, the themes of diversity, acceptance and inclusion in our movie are dear to my heart".

"[51] Casarosa later stated that the film was intended to be a metaphor for race and while romance was briefly discussed, it was never meant to be a focal point to the story; "some people seem to get mad that I'm not saying yes or no, but I feel like, well, this is a movie about being open to any difference.

[54] The film features songs by Mina, Edoardo Bennato, Gianni Morandi, Rita Pavone and Quartetto Cetra, and excerpts from operas by Giacomo Puccini and Gioachino Rossini.

[58] On January 19, a promotional still was released on the cover of Italian magazine Il Venerdì di Repubblica, featuring Luca, Alberto, and Giulia on a Vespa in one of the scenic backdrops from the film.

[66] Luca had its premiere on June 13, 2021, in Italy at the Aquarium of Genoa, with a three-day run by the non-profit organization MediCinema to raise funds for the Istituto Giannina Gaslini and other entities in the Ligurian territory.

[70] According to Nielsen ratings, following its opening weekend, Luca topped all original movies in its first days on streaming, with 1.573 billion minutes of viewing time.

The website's critics consensus reads, "Slight but suffused with infectious joy, the beguiling Luca proves Pixar can play it safe while still charming audiences of all ages.

[75] Alonso Duralde of the TheWrap wrote: "Luca is sweet and affecting, capturing the bond that strangers can build over a summer, and how that friendship can endure.

The play of light on the gloriously blue water's surface is almost photorealistic at times, while a sunset spreading its orange glow over rocks on the shoreline makes you yearn to be there.

"[77] Charlie Ridgely, writing for ComicBook.com praised the film for its uniqueness, saying that it highly deviated from Pixar's usual narrative formula and clichés, but that this didn't make it "lesser" than the company's classics like Toy Story and Up.

The studio's trademark daring, pin sharp sight gags, and big ideas are missing from a fishy coming-of-age yarn that's a little damp around the edges.

The cast expressed interest in returning for a sequel, and presented different ideas of what it would be about, among which was the joking suggestion they frequently made of giving Uncle Ugo a spin-off series.

Casarosa expressed interest in doing a sequel that would be similar to The Parent Trap, which would center upon Luca and Giulia's attempt to reunite Massimo and his wife.