Papua has the lowest literacy rate compared to other Indonesian provinces due to its limited education access. Exacerbated by teachers' absenteeism and lack of available reading resources, improving literacy in Papua is challenging to address. Our study aims to improve students' literacy through school literacy programs. A quantitative approach was employed on Grade 3 students (N=4,111) from 171 schools. Data were analysed through a framework of core reading competencies covering letter knowledge, word recognition, decoding, reading fluency and reading comprehension. We found a significant correlation between children's literacy competencies, their enrolment in kindergarten/ ECD (Early Childhood Development) centres, and the use of children's first language. Improvement of access to ECD centres and acknowledgement of students' mother tongue are important supports for literacy education in rural areas.