<p>Tampons are widely used hygiene products, yet there remains a lack of engineering-focused research on their design and functionality. A critical factor in tampon performance is the pore structure of the material, which directly influences liquid absorption. While micro-computed tomography has provided valuable insights into overall pore volume, it falls short in accurately characterizing individual pore sizes. In this study, we employ the sub-network of an over-segmented watershed (SNOW) algorithm alongside PoreSpy to obtain a detailed pore size distribution within tampon proxy materials. Our findings reveal that tampon proxies made of trilobal cellulose viscose fibres exhibit significantly larger pores, with a &#xa0;26-32% higher pore equivalent diameter (PED), than their round-fibre counterparts, despite comparable porosity, highlighting the influence of fibre geometry on expansion and liquid uptake. Although trilobal CV tampon proxies exhibit a 41% greater expanded volume and 18.7% higher absorbency compared to round fibres, their porosity increases only moderately, underscoring the need to investigate pore structure beyond bulk metrics. Kolmogorov–Smirnov distance analyses confirm that inter-fibre differences in pore structure exceed intra-sample variations, underlining the dominant role of fibre type on absorbency. While gradients along the tampon proxy length influence local pore formation, trilobal fibre tampon proxies consistently form larger pores, enhancing their liquid absorption properties. Additionally, we observe a systematic increase in pore size from top to bottom, likely influenced by one-sided liquid application and compression effects during production. These results offer a more detailed understanding of the mechanisms governing pore formation in tampon networks and provide a basis for future simulations of liquid imbibition, ultimately contributing to optimized tampon designs</p>