The three best collapsible running cups for races are the Nathan Reusable Race Day Cup (2-pack), Ultraspire C2, and JBER Silicone Collapsible Travel Cup with Lid. They’re lightweight, 7–8.79 oz capacities, and BPA-free silicone or food-grade plastics. They pop open fast and fold compactly for easy sips through aid stations, with simple cleaning and durable hinges. Each offers clear measurement marks and lids to keep debris out. If you want more specifics, you’ll find them here as you continue.