The ethnic and cultural diversity of today's society calls for sustainable intercultural education in an inclusive environment. The inclusion of newcomer children in the Latvian education system has become a topical issue with the Russian invasion of Ukraine. The preschool period is the time when the foundation for future achievements is laid; in an inclusive environment, children's knowledge and skills are fostered to find solutions in the sustainable society of the future. The readiness of preschool teachers for working with newcomer children is determined by the set of competences teachers have in place for the successful inclusion of newcomers in preschool education. A preschool teacher's competence to work with newcomers is a complex construct which includes many sub-competences. In their research, the authors identify knowledge, skills and attitudes that characterize a teacher's work with newcomer children in an inclusive environment. The results show that Latvia's preschool teachers lack the knowledge and skills for working with newcomer children, and their attitude towards these children is not always positive.