Research has shown that the domestic pig is highly playful throughout its development and that play is an important aspect of social and cognitive development. Therefore, the neonatal environment is fundamental to successful stimulation of play in neonatal pigs, which could have indirect and direct socio-cognitive effects on pigs post-weaning and therefore influence social interactions known to cause welfare concerns (e.g. aggression during mixing). This study investigated how play pre- and post-weaning developed in two neonatal environments (NE); the conventional farrowing crate (NEC) and a more environmentally complex alternative PigSAFE pen (NEP) and to discover whether this had an effect on piglet’ cognitive abilities in spontaneous object recognition tests for two retention times (15 and 60 min) post-weaning. Hourly focal sampling was used to record play behaviours pre- and post-weaning in 72 piglets of mixed sex (36 per NE) from a total population of 117 piglets from 12 litters. Out of the 72 piglets, 24 were used in the cognitive spontaneous object recognition tests five weeks post-weaning. Linear mixed models showed that NEP piglets displayed play behaviours quicker after birth than NEC piglets: locomotor (F = 7.62(1, 11), P = 0.020); sow interaction (F = 5.27(1, 11), P = 0.045); and social interaction (F = 23.61(1, 11), P < 0.001). NEP piglets played more pre-weaning than NEC piglets (F = 5.06(1, 71), P = 0.051) and despite initial higher levels of aggression at weaning, displayed less chronic aggression post-weaning as indicated by lesion scores of all piglets (F = 27.05(1, 116), P < 0.001). NE was shown to have a significant effect on the 15 min cognitive retention test; with NEP piglets spending more time interacting with the novel object than the familiar, compared to NEC piglets (F = 5.39(1, 23), P = 0.045). There was no NE effect for the 60 min retention test. It was concluded that play is fundamental to successful socio-cognitive development (e.g. aggressive conflicts) and relates to play function theories of training for the unexpected. Its effect on play behaviours are short-term and highly dependent on present environmental stimulus, suggesting that any long-term benefits play may have on an animal's welfare can only be achieved by regular stimulation throughout its life (e.g. constant enrichment).