Erika Kurumi, alias Cure Marine, joins the united Pretty Cure team in *Precure All-Stars DX3 Mirai ni Todoke! Sekai o Tsunagu Niji-Iro no Hana* to confront Lord Black Hole, an entity born from merged remnants of former foes. Amidst chaotic mascot showers disrupting a mall gathering, she encounters Cures from other series, including *Suite Pretty Cure♪*'s Hibiki and Kanade. Erika teasingly probes if they are Pretty Cures, noting their possession of a talking cat, though they initially sidestep her suspicion.

When Lord Black Hole's minions attack, targeting the Prism Flower—Earth's vital link to fairy realms—Erika transforms alongside her allies. Separated from her primary partner, Cure Blossom (Tsubomi Hanasaki), she finds herself grouped with Cure White, Cure Egret, Cure Aqua, Cure Mint, and Cure Berry within an oceanic shipwreck dimension. This team devises a strategy to shatter their crystalline prison, though distractions and enemy strikes hinder initial efforts.

Witnessing the mascots' despair as the fading Prism Flower threatens to sever Earth's ties to their worlds, Erika shares their distress. In a pivotal moment, she clings to Karen (Milk) after the Cures revert to civilian form. Later, surging global hope reignites the Cures' powers. Erika participates in a unified, upgraded transformation sequence and contributes her strength to the combined attack that ultimately defeats Lord Black Hole, preserving the Prism Flower's connection and ensuring continued visits between worlds.

Throughout the film, Cure Marine deploys her signature attacks: **Marine Shoot** (striking foes with summoned water droplets) and **Marine Dynamite** (unleashing explosive blue energy). Her personality remains true to core traits—energetic, bluntly expressive, and offering steadfast emotional support to allies during crises.