R.K.
I would have his doctor check him out. He's a little too old for these kind of accidents. One of my daughters has an enlarged bladder and renal reflux. She has trouble to this day (she's 16) getting the signal that she needs to go to the bathroom. And, often she can't just take a "maintenance pee" like most people do - you know - go even if you don't feel like you need to just because you won't have the chance for the next few hours. (To tell you the truth, I'm not sure if she physically couldn't or mentally couldn't!) For most of her childhood, she simply was unable to pee until her bladder was really full. Now in her teen years, she is more able to do this. But she had accidents in public several times over age 10!
She was what the doctor called an infrequent voider - someone who pees only twice a day. She was about your son's age and what I did to encourage her to go 5 times a day was to make colorful numbers and put a magnet on the back of them. Every time she peed, she got to put one on the refrigerator. She liked doing it. Oh, and the numbers had her name on them. It was just a silly little reward system that worked for a while.
Whether or not your son has some medical problem causing him not to realize he needs to go, finding a way to reward him for going to the bathroom before he has an accident could help prevent them. Maybe you buy him a watch that has an alarm and set it for two hours. When it beeps, he has to go to the bathroom, no matter what he's doing. When he comes to you, with dry pants, to reset his alarm, he gets some kind of reward. That will be fun and novel for a while. And it may get him used to the feeling of having dry pants.
Also - strong word of advice - if you take him to a urologist, go to a PEDIATRIC urologist. That's very important. Urologists are used to dealing with grown men, not children. Cardinal Glennon has a good team of pediatric urologists. My daughter doesn't need to go there anymore so I don't have a current name for you. But they have a good pediatric urology department.