Martial arts class for preteen

I highly recommend Aikido Shusekai in Berkeley. I and both of our children are students there, and it's been wonderful - the kids range in age from 7 to 12, and they do a superb job of working with each other, training in a focused way, and having fun. I train with the kids myself on Thursdays just because they bring so much new depth to my own practice, and it's been one of the most powerful bonding experiences I've had with them. Previous experience is not required in any way; several of the kids joined in September with no martial arts experience to speak of, and they're doing great. http://aikiarts.com/

Hanabi Judo in Albany at San Pablo/Solano. My son began there at 14 with no previous experience and easily transitioned into the community. He started going 3x a week and now, at 16, happily goes 5x a week and attends the tournaments. It has worked out really well and this was after a few fails.

I highly recommend Hanabi Judo in Albany. They are very family oriented and excellent with kids. For parents they have “parents night out” and summer camp for the kids. 

Hanabi Judo and Rohai Dojo are both good, with Rohai being a little 'softer' for encouraging.
But the way to do it is try several. They'll all let your child participate in a beginner class.

Both my son and daughter have been learning karate at Rohai Dojo (https://rohaidojo.com/) for several months and they both love it. 

My daughter used to go to a dojo which had a very different vibe (less friendly and accepting-- she eventually quit) and was initially reluctant to join her brother, but she has been totally won over by the kindness of the instructors to students of all levels/ages as well as the welcoming attitude of the other students. Everyone progresses at their own rate and it doesn't feel competitive, which is a relief to my kids. 

East Bay Seido Karate, on Bonita Avenue near downtown Berkeley, runs classes specifically for 9-15 year olds. My teenage daughters have been studying at that dojo since they were 5 years old, but beginners are always welcome, and the current cohort of kids is really great - supportive, respectful, and encouraging of each other. I don’t know if you live in Berkeley, but if your son sticks with it and attends Berkeley High, he would be able to earn PE credit through his training at East Bay Seido.

Studio Naga in Oakland @ Emeryville border.  Took my twin girls there @ 11 with no previous experience and one still training today at a sister school in Boston 15 years later.  Studio Naga has caring and knowledgeable staff, encourages "broken mirror" style of training and is a true art as the classes actively work on leadership and personal growth while learning the physical aspects of the art.

There are 5 classes a week for your family to choose from to fit with your schedule.  And speaking of family, family training is encouraged.  I started with my kids and continue to train.  It taught me to listen, interact and support my kids in a bigger way than I thought possible.

Studio Naga, 5850 San Pablo Ave, Oakland 94608

StudioNaga.com

Info [at] StudioNaga.com

510.652.6242