Managing dietary phosphorus is critical in advanced chronic kidney disease (CKD), where excess intake can lead to complications such as hyperphosphataemia. Plant-based milk alternatives (PBMAs) are increasingly consumed, yet their phosphorus content, particularly in relation to phosphate additives, remains poorly defined in the United Kingdom. This study aimed to quantify and compare the total phosphorus content and phosphorus-to-protein ratio (PPR) in a range of commercially available UK PBMAs, with and without phosphate additives, using ultra-violet (UV) spectrophotometric analysis.