In recent years there has been more and more emphasis on play in the Early Years setting. Play is important because it is inquiry in the truest sense. It is student-initiated and it involves freedom and choice and therefore builds agency and develops skills. It is through play that children move from dependence to independence through building their self-regulation. Because of this, Early Years students need extended time for play, and the adults should use this time to monitor and document the learning through inquiry that they observe happening.
There is a multitude of research that points to the development of skills through play, as both cognitive processes and social engagement are activated. These skills include language, symbolic exploration and expression, literacy and numeracy, all vital for any future learning. See the diagram below from The Early Years in the PYP publication.