The Science, Technology, Engineering, and Math Student Experiences Aboard Ships (STEMSEAS) program began, as many inspiring ideas do, on the back of a napkin. Author Cooper has worked for many years for the International Ocean Discovery Program (IODP) and its School of Rock, which provides teacher professional development workshops on the drillship JOIDES Resolution (JR). Author Lewis, an academic, is fortunate to have sailed twice as a School of Rock instructor on the JR and had been pondering since 2013 how undergraduates might be provided similar opportunities. Having but one JR that is usually in far-off waters presented an obvious challenge. Over coffee in Pittsburgh one day, we discussed the fact that the 19 ships of the University National Oceanographic Laboratories System (UNOLS) often have repositioning transits as well, and these voyages frequently sail out of US ports without full science parties, meaning there are multiple available berths. Why not use this capacity to provide undergraduates—particularly those from underrepresented groups—the engaging opportunity to climb aboard a research vessel and experience what it’s like to conduct research at sea? We are well aware that the geosciences overall, and oceanography in particular, lack diversity (NRC, 2011; NSF, 2011; Slovacek, 2011; Wilson, 2014), and these transits seemed like a perfect opportunity to address this issue in one small corner of our world.