Of course! If you’re using an eddy+ bottle, just be aware that the change in pressure can force extra fluid into the straw, which might cause it to spurt on the first sip or when flipping up the bite valve. Open with caution after take-off. You can relieve the pressure by unscrewing the cap a quarter turn prior to opening the bite valve. Your Podium and Chute bottles will work normally in high altitude situations.