Natural Rubber (NR), known for its superior properties compared to synthetic variants, owes its performance to its complex microstructure. This review explores the critical role of rubber particle size distribution, specifically large rubber particles (LRP) and small rubber particles (SRP), in defining NR’s unique characteristics. LRP, primarily found in concentrated NR latex (CNR), contrasts with SRP, which is typically sourced from CNR production waste (skim latex). The review begins with an analysis of NR’s microstructure, followed by a detailed examination of rubber particles (RPs). It assesses LRP and SRP, focusing on particle size distribution, molecular weight variance, and non-rubber components (NRCs). The review highlights how rubber particle size significantly influences the physical, curing, and mechanical properties of NR. By providing insights into LRP and SRP characteristics, this study aims to drive advancements in rubber product development, potentially revolutionizing the natural rubber industry.