The terahertz frequency band offers significant spectrum resources for next-generation wireless communications and ultra-high-resolution imaging for non-destructive sensing applications. Terahertz sensing and communications are inherently integrated for practical applications, while existing technologies typically focus on either point-to-point high-speed communications or high-resolution imaging. Here we demonstrate a portable 220-GHz-band device with a compact size of 20 × 20 × 10 cm3 that simultaneously realizes terahertz integrated sensing and mobile communications. The prototype is developed using high-temperature co-fired ceramic technology, featuring a phased-array frontend. Mobile communications is experimentally validated, achieving 64 Gbps data rate over 38 m with a ± 30° scanning range. With 100% shared hardware and orthogonal frequency-division multiplexing waveform, the device supports millimeter-level sensing accuracy. Incorporating a compressed-sensing algorithm further allows free-trajectory scanning, eliminating the need for time-consuming raster scanning. This work establishes a foundation for terahertz integrated sensing and communications, and provides crucial support for future applications such as autonomous vehicles, industrial automation, 6G networks and beyond.