Background: Frontline health-care workers have traditionally travelled away from their job sites to receive continuing education and training, which not only disrupts continuity of patient care but also incurs travel costs and causes scheduling issues. Asynchronous e-learning is an effective, non-disruptive, and economical alternative to the traditional model of continuing education and training. However, in resource-constrained settings, poor access to computers and unreliable internet connectivity have slowed implementation of e-learning. Here, we report on the effectiveness of our flexible, open-source method for the delivery of distance training on Android tablets that does not require access to the internet. Through five training programmes we aimed to assess learner satisfaction, costs compared with traditional training models, technical feasibility, completion rates, and challenges affecting implementation to continuously improve our framework. Methods: Five tablet-based training programmes were developed by the University of Washington Department of Global Health E-learning Programme (eDGH) and delivered in Namibia, Tanzania, and Zimbabwe. Participants were health care professionals, including clinical assistants, frontline health care workers, primary counsellors, pharmacists, physicians, nurses, and community health workers. The training programmes preserved much of the experience of a traditional online course, with videos, assessments, and interactive features such as discussion forums via the messaging application WhatsApp. Training programmes included a 24-month clinical officer training, month-long trainings on prevention of mother-to-child-transmission of HIV and child and adolescent HIV counselling, interactive job aides for clinical mentors, and health information systems. Tablets were usually loaned to participants for the duration of the training. Implementation partners included non-government organisations and ministries of health. Data collection methods varied by project but included focus group discussions, structured interviews, and online surveys. Findings: We included data from 248 participants who completed one of the five training courses between November, 2014, and September, 2016. For training programmes that evaluated learning with pre-tests and post-tests, the target audience demonstrated increased learning, although pass rates differed between programmes. In Namibia and Tanzania, per person costs for the tablet-based version of the training programme was about three times less than the in-person training. Because participants completed most of their training at the job site or home, off-site time decreased from 4 days for the in-person training to under 1 day. For training programmes that used text messaging to keep learners engaged, all participants finished in the time allotted. Overall, feedback showed that participants are enthusiastic about the tablet-based training. In Zimbabwe, many participants reported sharing the training programmes with co-workers and several participants requested more ways to engage with other learners. The training programme in Namibia and Tanzania had no technical difficulties with the tablets, while in Zimbabwe there were minor issues with the software. Interpretation: We plan to improve flexibility and usability of e-learning programmes through additional testing to ensure users on all devices have the best learning experience possible. We will continue to expand the types of learning activities and incorporate more real-time interactions among peers and course facilitators through text-message-based discussion groups or added face-to-face interactions for participants at the same facility. Funding: The President's Emergency Plan for AIDS Relief (PEPFAR), and Centers for Disease Control and Prevention. more...