The SEG 2015 Annual Meeting postconvention workshop, “Next-generation marine seismic sources,” provided an opportunity to summarize the current areas of new marine seismic source development and how they relate to the drivers of operational efficiency and environmental sensitivity. The session included presentations from marine seismic regulators on their current goals and challenges with respect to the permitting process and from several joint industry projects in these areas. The presentations provided perspectives on the expectations that environmental interest groups, regulators, and industry have with respect to the next generation of marine seismic sources. A number of recently developed, emerging, and potential marine seismic source projects were presented with their current project status, representing state-of-the-art marine seismic source technology. Periods of open discussion between the panelists, presenters, and audience covered efforts to modify existing source technology; compared continuous sources, such as marine vibroseis, with conventional impulsive sources; and discussed the need for additional research to evaluate the optimum output characteristics for continuous sources and to assess their environmental impact. The workshop demonstrated that there is still a high level of activity in the industry to develop alternate seismic sources and assess their environmental impact — even during economic downturns.