The Mote Ocean Technology Club, a new outreach program at Mote Marine Laboratory in Sarasota, Florida, implemented state-of-the-art technology to engage 12 high school students and four teachers during a semester-long afterschool STEM program. Club activities were broad and interdisciplinary, but the primary goal was to build inexpensive sensors and disseminate data streams to the Gulf of Mexico Coastal Ocean Observing System (GCOOS)— emulating the activities of many ocean-observing labs around the world. This article details club activities, provides links to the online curriculum, summarizes successes, challenges and recommendations for similar (or smaller) classroom-based efforts, and describes curriculum plans for the next phase of the club.