Yes, they will be able to hear the music if they are within a few feet of you. It's not loud, but it can be heard, especially if you have the volume turned up (they are not really loud, I have mine turned to 80-100% when I'm bike riding. I'm liking mine alot, but they are not earbuds where the music is directly pushed to your ear canal. Not as loud, not as bass-y. But, on the plus side, you don't have things sticking in your ear and you look way cooler!