Large-scale seasonal thermal energy storage (TES) can help maximize renewable energy integration into district heating and cooling (DHC) systems. However, expertise and concrete projects in the field is limited and there is currently a lack of reliable and adequate analysis tools and cost data to assess the technical-economic potential of aquifer thermal energy storage (ATES) or pit thermal energy storage (PTES). This paper provides a review summary for current ATES and PTES systems, including design concepts, application criteria, specific cost comparisons of various storage systems, as well as a summary of applicable modelling and design tools currently available.