Camellia japonica is a widely cultivated ornamental plant that also contains significant amounts of bioactive compounds, including polyphenols and essential minerals. Despite its distribution across Asia and Europe, the nutritional profile of C. japonica remains largely unexplored compared to other members of the Camellia genus, such as C. sinensis. This study aimed to characterize the mineral composition of C. japonica leaves and assess their potential relevance for sports nutrition. Analysis revealed that C. japonica leaves are particularly rich in calcium (≈8.3 g/kg) and magnesium (≈1.4 g/kg), as well as substantial potassium levels. These minerals are critical for athletic performance: calcium supports bone integrity and muscle contraction, magnesium contributes to energy metabolism and neuromuscular function, and potassium maintains electrolyte balance and hydration. Ensuring adequate intake is especially important for athletes engaged in high-intensity or endurance activities, where increased metabolic demands and sweat losses can compromise performance. ¹² Beyond their mineral content, C. japonica leaves may provide antioxidant compounds capable of mitigating exercise-induced oxidative stress and inflammation. The incorporation of C. japonica leaf extracts into functional foods or plant-based sports supplements offers a sustainable and locally sourced alternative to conventional supplementation. Future studies should focus on the bioavailability, safety, and efficacy of these extracts in athletic populations, paving the way for innovative nutritional strategies that enhance both performance and sustainability.