Early experience is known to be important in the development of mating behaviour. The behavioural and chemical stimuli obtained by observing adults interacting are thought to operate as template by which young acquire the ability to sexually display when appropriate. But, while the importance of early social interactions for the development of mating behaviour is well accepted, how social deprivation at different onto-genetic phases contributes for this effect is poorly understood. Here, we address this gap by asking how social deprivation at different ontogenetic phases (before or after 6 wk) mediates male mating behaviour in the Trinidadian guppy. We show that in the absence of early social interaction, the latency of mating behaviour is briefly delayed, but that all individuals were able to sexually display in <30 min. Interestingly, regardless of the timing of social deprivation, mating behaviour starts sooner under female-biased sex ratios environments that than under a male-biased sex ratio, suggesting that male sexual behaviour is driven by female cues. The short-lived effects of social deprivation on mating behaviour reflect the extraordinary innate plasticity of guppies, which is likely to contribute to their success as invasive species.