The World Health Organization estimates that up to half of vaccines are wasted, however only a minority of mHealth programs in Africa have been directed at vaccine supply chain optimisation. We piloted a novel mHealth solution dependent only on short message services (SMS) technology that allowed workers in rural health centres in Zambia to report vaccine stock levels directly to an online platform. Small airtime incentives were offered to encourage users to engage with the system, as well as weekly reminder messages asking for stock updates.The primary outcome measured was the percentage-of-doses-tracked, calculated over the study period. Each vaccine box was randomly allocated to offer either a standard or double airtime incentive and either weekly or daily reminders, in a 2 x 2 design; ANOVA was used to calculate if any of these factors affected time-to-reply.Over the study period, the total percentage-of-doses-tracked was 39.9%. Within the subset of users who sent at least one message to the platform, the percentage-of-doses-tracked was 93.8%. There was no significant difference in average time-to-reply between the standard airtime incentive and double airtime incentive groups, nor was there a significant difference between the standard reminder and daily follow-up reminder groups.This pilot study found that in an active subgroup of health workers, an incentivised mHealth solution was able to collect tracking data for 93.8% of doses. More research is needed to identify methods to encourage healthcare workers to engage in timely stock reporting practices.