Objective: To measure scenario participant and faculty self-reported realism, engagement and learning for the low fidelity, in situ simulations and compare this to high fidelity, centre-based simulations. Methods: A prospective survey of scenario participants and faculty completing in situ and centre-based paediatric simulations.Results: There were 382 responses, 276 from scenario participants and 106 from faculty with 241 responses from in situ and 141 from centre-based simulations. Scenario participant responses showed significantly higher ratings for the centre-based simulations for respiratory rate (P = 0.007), pulse (P = 0.036), breath sounds (P = 0.002), heart sounds (P < 0.001) and patient noises (P < 0.001). There was a significant difference in overall rating of the scenario reality by scenario participants in favour of the centre-based simulations (P = 0.005); however, there was no significant difference when rating participant engagement (P = 0.11) and participant learning (P = 0.77). With the centre-based scenarios, nurses rated the reality of the respiratory rate (P < 0.001), blood pressure (P = 0.016) and abdominal signs (P = 0.003) significantly higher than doctors. Nurses rated the overall reality higher than doctors for the centre simulations (96.8% vs 84.2% rated as realistic, P = 0.041), which was not demonstrated in the in situ scenarios (76.2% vs 73.5%, P = 0.65). Conclusion: Some aspects of in situ simulations may be less 'real' than centre-based simulations, but there was no significant difference in selfreported engagement or learning by scenario participants. Low fidelity, in situ simulation provides adequate realism for engagement and learning.