In 2021, California made major new investments to advance its commitment to early childhood education through universal preschool. One important investment was extending state funding for transitional kindergarten (TK), previously just for older 4-year-olds, to all 4-year-olds by 2025-26. To ensure the quality of new preschool investments, California must recruit and prepare a sufficient number of qualified teachers in TK and other early childhood programs--a challenge given the rapid expansion of the program. This challenge is even greater during the COVID-19 pandemic, when school districts and early childhood programs are facing significant staffing shortages. This report provides estimates of how many TK teachers California will need through 2025-26 and discusses potential pathways to support a diverse, well-prepared workforce, both in TK and in other early childhood programs. The authors also offer recommendations that state policymakers could follow to stabilize, support, and expand the broader early childhood workforce and to build pathways for racially, linguistically, and culturally diverse educators. [For the Research Brief, see ED622845.]