How do I keep my water cold while hiking?

There are a few ways to keep your water cold while hiking. One way is to bring a thermos of ice water with you on the trail. Another way is to fill up your hydration bladder or pack with ice and cold water, and drink from that throughout the hike. Finally, you can also fill up any plastic bottles or containers with ice and cold water, and place them in your backpack or on the ground next to you during the hike.