The aim of this study was to assess the potential of thermosonication as a strategy to obtain safe and high-quality tomato juice enriched in anthocyanins, formulated using strawberry processing co-products. Incorporation of strawberry press cake into the tomato juice resulted in higher polyphenolic and anthocyanin content and increased antioxidant capacity. Thermosonication for 5 min at 60 °C at either 35 or 130 kHz resulted in higher microbial inactivation when compared to thermal pasteurisation at 80 °C for 1 min. In addition, thermosonication allowed increased retention of colour attributes as well as polyphenol, lycopene, anthocyanin, and antioxidant capacity retention when compared to thermal treatment. For example, the total anthocyanin content decreased from 1.08 ± 0.04 mg/100 mL before processing to 0.92 ± 0.01 mg/100 mL after thermal pasteurisation but the difference was not significant when compared with the thermosonicated juice (1.06 ± 0.03 mg/100 mL). Although bioaccessibility of phenolic compounds after a simulated gastrointestinal digestion was lower in processed juices, thermosonicated samples showed a higher bioaccessibility when compared to the thermally treated ones.