Mobile devices (smartphones, smartwatches, etc.) allow us to reach people anywhere, anytime. Collectively, these devices form a ubiquitous computer that offers valuable insights on the user. In addition to the benefits for researchers and developers, explored in previous UbiMI workshops, devices can also help individuals understand their own health, activities, and behaviour. The Ubiquitous Mobile Instrumentation (UbiMI) workshop focuses on using mobile devices as instruments to collect sensing data, to understand human-behaviour and routines, and to gather users' context using sensor instrumentation.