The Internet of Things (IoT) is a rapidly growing field that necessitates long-range, low-power communication solutions, particularly in remote areas. Direct-to-satellite IoT (DTS-IoT) connectivity is an appealing option because it eliminates the need for ground-based intermediaries, thereby simplifying and accelerating the widespread implementation of IoT infras-tructure. Low Power Wide Area Network (LPWAN) technology, with its long-range connectivity and low power consumption, is well-suited for Massive Machine-Type Communication (mMTC), a key application of IoT. Furthermore, LPWAN technology shows potential for communication with Low Earth Orbit (LEO) satellites, which offer wide coverage and low latency, making them ideal for IoT device connection. This paper investigates the integration of LPWA technology with LEO satellite-based IoT, a crucial step toward advancing communication mechanisms in this domain. The paper provides a comprehensive survey of LPWAN technologies suitable for DTS-IoT applications. In the context of LEO satellite communications, it is essential to consider certain fundamental aspects. This includes the challenges faced by LPWAN technology in DTS-IoT on LEO satellites, such as the Doppler Effect, limited field of view, visibility windows, and random access. LoRa and LR-FHSS are two promising candidates for DTS-IoT on LEO satellites as they meet the link budget requirement at altitudes over 500 km. They also exhibit good Doppler resilience compared to other technologies; however, further research is necessary to confirm these findings. In summary, there is a need for future work in developing algorithms and implementing them in hardware to overcome the existing limitations.