SummaryThis study evaluated the composition of watermelon and mango juices fermented by Levilactobacillus (L.) brevis, Lacticaseibacillus (La.) casei and Pediococcus (P.) pentosaceus and subsequently simulated in vitro digestion and storage (4°C for 35 days). After fermentation (24 h), the microorganisms grew (~9 log CFU mL⁻¹) and fermented watermelon (FWJ) and mango juice (FMJ) became more red and yellow, respectively. DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) and ABTS (2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid)) free radical scavenging capacities significantly increased in L. brevis and La. casei FMJ. After in vitro digestion, all the strains except La. casei in FMJ significantly decreased (P < 0.05), and P. pentosaceus survival was 2.4 and 4.5 times higher in FWJ and FMJ, respectively, than as pure culture. After storage, cell counts remained above 7 log CFU mL⁻¹, and no changes in quality attributes, total phenolic content and antioxidant capacity were recorded in P. pentosaceus FMJ. Thus, watermelon and mango are suitable matrices for lactic acid bacteria.