Abstract: The demand for real-time positioning and time synchronization is increasing in environments such as marine and aerial settings. However, post-processing precision products suffer from long latency, and real-time correction products transmitted over networks are prone to interruptions due to network instability, which severely limits both real-time time synchronization and positioning accuracy. Therefore, this paper investigates time transfer and positioning technologies based on BeiDou-3 Navigation Satellite System (BDS-3) B2b correction products. We design two clock synchronization and positioning experiments and systematically analyze the satellite orbit and clock bias performance of BeiDou-3 B2b correction products, as well as the time transfer and positioning accuracy compared to existing network-based real-time correction products and ultra-rapid products. The experimental results show that the satellite clock bias accuracy of BDS-3 B2b correction products is better than that of real-time correction products but worse than ultra-rapid products. The satellite orbit accuracy is inferior to other products. For static PPP positioning based on BeiDou-3 B2b correction products, the 3D positioning accuracy is better than 5 cm, slightly inferior to other products, but the convergence time for single BDS mode is longer. The PPP time transfer accuracy for one day based on BDS-3 B2b correction products is better than 0.11 ns, and the frequency stability is better than 4.1×10⁻¹⁵ for a 6 000 s interval, with only minor differences compared to other products. Thus, the PPP time transfer technology based on BDS-3 B2b correction products can achieve subnanosecond-level time transfer and centimeter-level positioning in environments without network access.