A cyber-physical system (CPS) is a system of collaborating computational elements con- trolling physical entities. CPS represents the next stage on the road to the creation of smart cities through the creation of an Internet of Things, data and services. Mobility is one of the major characteristic of both CPS and IoT. In this Chapter, we discuss mobile sensing platforms and their applications towards dierent but interrelated paradigms such as IoT, sensing as a service, and smart cities. We highlight and brie y discuss dierent types of mobile sensing platforms and functionalities they oer. Mobile sensing platforms are more oftenly integrated with smart phones and tablet devices. The resource constrained nature of the mobile devices requires dierent types of designs and architectural implementations. We proposed a software-based mobile sensing platform called Mobile Sensor Data Engine (MOSDEN). It is a plug-in-based scalable and extendible IoT middleware for mobile devices that provide an easy way to collect sensor data from both internal and external sensors. MOSDEN act as intermediary device that collects data from external sensors and upload to the cloud in real-time or on demand. We evaluate MOSDEN in both stand-alone and collaborative environments. The proof of concept is developed on Android platform.