The increasing demand for plant‐based beverages with improved functional and sensory qualities has guided this study, which examines the bioactive content, functional, and sensory properties of a rice, apple pomace, and sea buckthorn beverage (RASB) fermented with probiotic Lactobacillus plantarum and Saccharomyces cerevisiae. We found out that total polyphenol content (TPC), total flavonoid content (TFC), and β‐carotene were significantly higher in samples with Saccharomyces cerevisiae, particularly in coculture samples. These samples also exhibited elevated alcohol by volume (ABV). Monoculture samples showed increased total flavonol content (TFLC), total anthocyanin content (TAC), and proanthocyanidin. The RASB‐LP sample, containing only Lactobacillus plantarum, revealed the highest antioxidant properties, evidenced by DPPH (94.13 ± 0.05%) and ABTS (97.69 ± 0.09%) assays. Interestingly, 3‐methylbutyl 3‐methylbutanoate, abundant in the unfermented control, was hydrolyzed to 3‐methyl‐1‐butanol in fermented samples, especially those containing Saccharomyces cerevisiae. Sensory evaluation evidenced that RASB‐LP scored highest for aroma and overall acceptability. FTIR analysis also indicated changes in functional groups of RASB samples. Together, our findings suggest that a novel probiotic cereal beverage with enhanced quality can be developed through the addition of fruit and fruit pomace, coupled with fermentation using Lactobacillus plantarum LP28 and Saccharomyces cerevisiae.