SATA III, or Serial ATA III, is a computer bus interface that connects storage devices like hard drives and solid-state drives to the motherboard. It offers a maximum data transfer rate of 6 Gbps, which is double that of its predecessor, SATA II. This increased speed allows for faster data access and improved overall system performance. SATA III is widely used in modern computers and laptops, making it a standard for connecting storage devices. It is compatible with older SATA versions, ensuring that users can upgrade their drives without needing to replace the entire system.