Today, the heating sector is not on track toward achieving the IEA Net-Zero targets: it represents more than a third of the energy demand and it mainly relies on fossil fuels. District heating is recognized as a major solution allowing decarbonization of the heating sector. The integration of large-scale seasonal energy storage, compensating for the mismatch between supply and demand whilst ensuring the service, is key for a wide spread of district heating. USES4HEAT aims to demonstrate innovative, large-scale, seasonal thermal energy storage solutions enabling a future decarbonized and reliable heating supply. USES4HEAT demonstrates, at TRL8 and for a one-year test campaign, two innovative, cost-effective, large-scale, seasonal underground TES units to maximize the availability and resilience of heating supply while reducing energy losses and environmental impact. USES4HEAT seeks to demonstrate the storages as fully integrated units in commercial large-scale district heating networks and industrial waste heat recovery and fulfilling industrial thermal demand. In doing so, USES4HEAT also demonstrates six innovative key enabling components/technologies and their integration with seasonal storages: advanced drilling equipment and remotely controlled machines halving drilling times, innovative layered high-temperature borehole pipes, efficient groundwater heat pumps integrated with aquifer storages, hybrid solar panels and thermal solar collector, and accurate AI-based energy management tools. USES4HEAT will systematically demonstrate the effectiveness and techno-economic-social viability of innovative, large-scale, seasonal energy storages ensuring limited CAPEX, reduced environmental impact and energy losses, efficient integration in district heating and accumulation of various sources of heat, and granting reliable and decarbonized heating supply.