Since the year 2000, the provision of early years education and care for the under-threes (hereafter 0-3 ECEC) in Spain has undergone a steady increase. This growth has taken place in all of the seventeen Autonomous Communities, albeit not in a uniform way. In this article we study how different institutional designs at the regional level have an impact on equality of opportunities, both in how families access the service and in how much they pay. We try to ascertain under what conditions ECEC can go beyond a policy that helps families juggle work and family responsibilities, and becomes a redistributive and equal opportunities policy that helps the most socially disadvantaged groups access it while defraying its cost. We analyse how state regulations regarding ECEC have evolved from the 1990 LOGSE to the 2020 LOMLOE, and we compare seven Autonomous Communities which each have different levels of coverage and management models. Our study concludes that although there are differences in both access criteria and in the price of services, all the Autonomous Communities studied have been moving towards a service that aims to be more equitable, with an explicit recognition of the particular difficulties caused by low income, disabilities, being a single parent, or gender-based violence. Even so, certain structural characteristics of ECEC -such as the fluctuating nature of its financing, its weak public regulation and monitoring, and significant outsourcing to private providers- make it difficult to universalise the service in order to make it a truly redistributive policy.