This article describes an open source Unmanned Surface Vehicle (USV) designed to operate in indoor laboratory environments. The microUSV is small (23cm long) and inexpensive (approximately $320 per nit for 10 vessels): an ideal hardware platform for algorithm validation and marine swarm robotics research. The primary design goal was to minimize the vehicle’s size and cost while providing a stable and maneuverable platform with onboard autonomy. To that end the vehicle is built using 3D printed and off-the-shelf hobbyist electronic components and uses an overhead camera system to simulate sensor data to minimize the number of onboard sensors required. This article describes the context, design, and assembly procedures for a microUSV and demonstrates the platform’s base-level functionality in the form of a waypoint following controller implementation for both single and multi-robot configurations.