This book constitutes the refereed proceedings of the 3rd R Day, held in Medellín, Colombia, on November 14, 2025.The 21 full papers included in this volume were carefully reviewed and selected from 43 submissions. The papers focus on the use of the R programming language for statistics and data analysis, and cover the following topical sections: Development of packages and tools in R; Applications of R in multiple disciplines; Time series analysis with R; Teaching and pedagogy with R, and Biostatistics with R.

This book constitutes the refereed proceedings of the 3rd R Day, held in Medellín, Colombia, on November 14, 2025.The 21 full papers included in this volume were carefully reviewed and selected from 43 submissions. The papers focus on the use of the R programming language for statistics and data analysis, and cover the following topical sections: Development of packages and tools in R; Applications of R in multiple disciplines; Time series analysis with R; Teaching and pedagogy with R, and Biostatistics with R.