The site, created by the Catholic Agency to Support Evangelization, features more than 20 interactive pages covering music and film, "Girls only" and "Boys only" sections, book reviews, prayer and a questions area.
"Step Ahead" interviews feature teenagers 14-16 years old who serve as older role models.
Emily Davis, one of the Yfaith creators, said research suggests courses on religious studies continue to increase in popularity.
"Yfaith is a resource which aims to encourage and support children and young people in their journey of spiritual discovery and enquiry," she explained. "We hope that there is something on the site for everyone."
Central to the site's strategy is that it has been molded, and in parts co-written with adults, by the target age group.
James, 12, who attended a pre-launch children's party. said: "The site is easy to understand. The things they say you can really relate to."
Laura, 11, said: "I think it's really good. It tells you about things you want to know and it tells you about what other people have said."
Yfaith is designed to complement what children receive in the classroom and enable them to discover the contribution they can make to the world at large. It places particular emphasis on children's spiritual questions and interests.