Lynden Prosser is an American voice actor known for providing the English voice for the main character Umi in the 2019 anime film Children of the Sea. He began pursuing acting at the age of five, starting with local theatre and acting camps before booking a commercial. To prepare for voice-over roles, he has studied acting and voice with a coach in New York City.

His most prominent role to date is Umi in the animated fantasy film Children of the Sea, directed by Ayumu Watanabe. Prosser, who was twelve years old at the time, was cast in the lead role after submitting an audition tape recorded at home. The character Umi is a mysterious boy raised in the ocean by dugongs, who possesses special powers related to the sea. Prosser recorded his dialogue at a studio in New York City, a process that involved matching his voice to the character's on-screen body language and took just under ten hours to complete. The film's director provided instruction remotely via video call during the recording sessions. The English-dubbed version of Children of the Sea, featuring Prosser, was released in 2020.

Prior to Children of the Sea, Prosser provided voice work for a Ukrainian film titled Polina. Information about recurring collaborations with specific directors or voice actors is not available in the search results.