In 2012, engineering was adopted as a content area in K-12 science education. Yet few science teachers have engineering content or pedagogical content knowledge. Teachers learn how to teach engineering through professional development experiences, for which Darling-Hammond et al. (2017) outline seven characteristics of effectiveness. This mixed-methods study compared three cohorts of the NSF-funded Research Experiences for Teachers (RET) participants at one university. Two cohorts of in-service teachers experienced RET on-site, and one (summer 2020) experienced the program 100% remotely, due to COVID-19. Research questions explore 1) the extent to which the RET program delivered in-person and remotely reflected the seven characteristics of effective PD; and 2) whether program outcomes of the hands-on, lab-based program could be achieved remotely. This study found that six of the seven characteristics of effective PD were fully evidenced in all three RET cohorts, and one was partially evidenced. Program outcomes were achieved at high and comparable levels for all cohorts, though the nature of the experience varied by mode of delivery. This research contributes to existing literature that finds no inherent differences in the quality of teacher professional development delivered in-person or remotely.