California's 2020 Master Plan for Early Learning and Care gives the state's families choice among programs and providers--private or public, subsidized or unsubsidized (if eligible), offered in schools, child care centers, and family child care homes. This landscape changed significantly with the introduction and subsequent expansion of Universal Prekindergarten (UPK) to be available to all four-year-olds by the 2025-26 school year. Transitional Kindergarten (TK) is one of California's Early Childhood Education (ECE) options for families with preschool-aged children. It is free, provided by the K-12 system, and meant to use curriculum, instruction, and facilities developmentally appropriate for four-year-olds. First offered in 2012-13 only to children turning five in the fall, TK participation grew from 17 percent of eligible children to a peak of 83 percent in 2018-19. The pandemic brought enrollment and participation rates down considerably in 2020-21 and 2021-22. TK's very first year was only for children born in September and October. After state changes to the birthdate cutoff for kindergarten, the program accommodated children born between September and December who were now too young to be eligible for kindergarten. UPK introduced further expansions of age eligibility--starting in 2022-23 with children born between December and February and gradually adding those born before April, June, and September over the next three years. By 2025-26, all four-year-olds will be eligible for TK in California. While TK enrollment is optional for families, all school districts with kindergarten must offer it and provide age-eligible children a slot. For public school districts funded by the Local Control Funding Formula (LCFF), TK is paid for through average daily attendance (ADA) just as other K-12 grade levels. Some districts do not receive funding from the state because their property tax revenue is at least at the level of what the district would receive under the formula. Known as Basic Aid districts, they are primarily funded by local property taxes rather than LCFF and as a result, they do not receive additional funding per TK-enrolled student. Building on previous PPIC research, this report examines how school districts and families throughout the state are responding to TK's increased availability, using the most recent data available from 2023-24. The authors estimate overall take-up rates among eligible four-year-old children and look at the accessibility of TK programming by estimating the number not enrolled. The authors then analyze whether program take-up differs across student characteristics--including race and ethnicity, home language, and disability status. To complement the analysis of enrollment trends, the authors discuss insights from interviews conducted with ten school districts--including districts that have opted not to provide TK. The conversations with districts provide important context for the types of challenges and successes districts are experiencing on the ground, as well as how TK provision supports DLLs and students with disabilities.