Electronic gaming machines (EGMs) and other gambling-themed simulators are a popular sub-genre of video-games or “apps” played on mobile devices (King et al. in Comput Hum Behav 31(Supplement C):305–313, 2014). Qualitative evidence suggests that some people use gambling-themed simulators in an attempt to limit their real-money expenditure (Thorne et al. in J Gambl Issues 34:221–243, 2016), although playing such games might also encourage gambling due to anticipated enjoyment or profit. To test the potential relationship between use of simulated mobile gambling products and real-money gambling, a study was devised to explore current and retrospective accounts, as well as a prospective trial of how weekly play on EGM simulators might influence subsequent gambling. A total of 736 EGM gamblers (421 male) completed an initial scoping survey on their current and retrospective use of simulated and real-money gambling products. By invitation, 556 people (314 male) from the initial survey also volunteered in a 24 weeks follow-up study where approximately half (48.2%) were randomly assigned to play a simulated game, “Lucky Lolly Slots”, for at least 5 min each week. Simulated gambling sessions were recorded for both Lucky Lolly Slots and any other gambling apps played by the participants. Results showed that people who had played gambling-themed EGM apps at some point in their lifetime had a higher frequency of play on real-money EGMs and were more likely to admit to current gambling problems. In addition, those people who played a simulated EGM app prior to age 13 nominated an earlier age at which they “gambled the most” in adolescence. In the 24 weeks trial, people’s app play (number of sessions) in 1 week reliably predicted increases in real-money gambling the following week. We found no evidence that people who were trying to reduce their expenditure were contrarily influenced to gamble less as a result of their app play, with their app-sessions similarly being related to increases in expenditure. The present results suggest that gamblers who play simulated games are likely to be influenced to gamble more on real-money forms of gambling as a result of their use. The study raises particular concerns about the widespread availability and popularity of such gambling-themed simulators amongst children and adolescents.