How do I know? Well, I tested some myself, polled Cosmo editors for their expert recs, and combed through reviews to find the best water bottle sling bags and bring them straight to you.

Perfect for a day hike.” If you’re looking for extra versatility, this fanny pack with a water bottle holder converts to a sling bag to be worn over your shoulder. Made of water-resistant ...

I got the Béis Sport Sling in Olive—the brand's newest ... Unlike the Béis bag, the Calpak Water Bottle Holder doesn't have multiple zippered compartments or space in general.

The solution? A water bottle sling. Most sling and belt bags are small by definition, which means you're lucky if you can fit your wallet, phone, and sunglasses inside, let alone a whole hydration ...