This paper outlines the longitudinal development of a K-12 outreach model, to promote Computer Science in Ireland. Over a three-year period, it has been piloted to just under 9700 K-12 students from almost every county in Ireland. The model consists of a two-hour camp that introduces students to a range of Computer Science topics: addressing computing perceptions, introduction to coding and exploration of computational thinking. The model incorporates on-site school delivery and is available at no cost to any interested school across Ireland. The pilot study so far collected over 3400 surveys (pre-and post-outreach delivery). Schools from all over Ireland self-selected to participate, including male only, female only and mixed schools. The no-cost nature of the model meant schools deemed "disadvantaged", to private fee-paying schools participated. Initial findings are very positive, including the balance of male and female participants, where in the 2017-18 academic year it was 56:44 and in 2019-20 (to date), it is 35:65 respectively. Once the model is validated and tweaked (based on survey data), the model will be published (open access) for other institutions to implement the model locally. In addition, the authors intend to link schools (that the team have worked with over the three years) with local institutions, thus developing a sustainable ecosystem for the program to continue. This paper describes the model structure and outlines early findings. CCS CONCEPTS • Social and professional topics → Computer science education.