This paper aims to focus on the international studies regarding early integrated STEM education and its importance for developing 21st-century skills in young children to prepare them for an ever-changing world. The paper reviews the importance of integrated STEM education in early childhood settings and how it supports the development of scientific concepts and 21st-century skills such as critical thinking and problem solving through play-based learning based on the current literature. Adding to the importance of STEM education, the paper explores what STEM education means in early childhood and how different types of play-based learning can support early integrated STEM concepts and skills in young children concerning the literature from different parts of the world. Furthermore, the literature presents the role of teachers in implementing STEM practices and the challenges encountered by teachers. The literature indicates low self-efficacy and confidence in teachers as the main factor affecting the delivery of STEM teaching and suggests ways to overcome this through STEM professional development to enhance the STEM practices in early childhood. The paper concludes with further recommendations and implications for stronger policies, and more research in this field to achieve high-quality integrated STEM education in early childhood.