I got my black belt from here. The best place in the East Bay! They are the nicest family and are extremely professional. Behind their caring attitude are constructive teachers that can push you to be your best if you want to be! Sifu Tim has many years of experience and training that will make you feel like you're in the right hands. He understands the real world, and knows how practical self defense is the most effective personal safety measure. I highly recommend this place to anyone looking for quality self defense training. read more

My son Ty , 13 yrs old, tried his first class at D-1 yesterday and I was impressed. Not intimidating at all . All instructors were able to cue in on my son's challanges and help him move forward without embarassing him or making him feel inferior. Even though others were present instructors took the time to show him the correct way without singling him out. This was impressive to me because many times students get lost in numbers. Another element that stood out was respect. Not just at a martial arts level, but truely sincere level of respect towards others. Great first impression! read more

First, I want to apologize because I should have reviewed this place a very long time ago! I have trained at this location for at least the last 6 years. I remember the first time I had to stop attending classes because I was moving. I had asked Sifu Tim if he could recommend another kaju school in the area I was moving to and he was very gracious about it. What I realized is I could not (and still cannot) bring myself to train elsewhere. Ms. Tammy and Sifu Tim are ohana and they foster an environment which has become a haven for me and provides a sense of well being. When I walk into the dojo - I am there in the moment and the world melts away. Do not get me wrong. Training is not a cake walk, it is rigorous especially as you move up in rank but is fun and rewarding. Sifu Tim and the other instructors care about the art and form. They take the time to teach you what proper technique and explain the purpose of each move and even teach you one on one. Sifu Tim, Ms Tammy and et al. are family-centric. They not only care about the art but about the student (whether adult or child). They are involved in building up the confidence levels of students by participating in mentoring programs, group outings, and giving back to the communities. I LOVE THIS PLACE!! read more

My grandson attend the D1 & Only Martial Arts. He enjoys his class when he's there and looks forward to going to class. The staff and the instructors are wonderful. One thing I really like about the center, they are very concerned about the well-being of the child education. And you have forms to fill out and the child teacher to fill out as well. There are consequences for the child if he's not doing well at school or home. This is a great learning experience for the child and it makes one confident and responsible. I would recommend anyone, even you! read more

I am so happy my coworker told me abt this place. The Sifus (instructors) r fantastic!! They're obviously very skilled in the art and r passionate abt teaching and interacting with all the kids. I haven't stopped smiling since I stepped thru the doors bc the environment is super welcoming and the kids of all ages just love being here :) read more

Looking for a great place for you or your child/children to take Karate/Self Defense??? There is a great place in Antioch called "D-1 & Only Martial Arts" Academy, Inc. They feature anti-bullying, women's self-defense, children's ID cards, etc. They are especially great with everyone, especially children. They are the nicest, most respectful teachers, and they teach their students to have the same respect for everyone. For more information, you may check out their website @ http://www.deltaoneinc.com. Or you can call them at: (925) 753-1167. read more

My family and I started here over 10 years ago. Now, me, my husband, my son, my daughter, my nephew, my niece, and my brother-in-law have all earned at least one black belt each (some of us have 2 or 3 degrees, even!). This school is our home away from home. The Master Instructor, Sifu Tim Calvin, is an amazing teacher. He is patient with kids and adults alike, but firm. His son, Chief Instructor Sifu Jarrell Calvin, has followed in his father's footsteps and has become a great instructor as well. They teach practical martial arts (Kajukenbo, kickboxing, grappling, and more) and focus on real-world situations. They not only keep focus on martial arts, but encourage academics, respect, and discipline while in a safe and comfortable environment (No Cobra Kai here!). I truly believe that my children are more confident, respectful, and successful because of their time here. I, myself, was pretty shy before I started here and they have enabled me to come out of my shell, be confident, and be an advocate for myself and others. I highly recommend this establishment as it is family run and family-friendly. Five stars is not enough! read more

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I first went there, 2 days after my birthday. I was 13 at the time and I got bullied in school. My grandpa was tired of it and Tried to find a good karate school. Most schools were expensive but my Uncle suggested Delta one, since my cousin went there and is a black belt. So my grandpa went there and Enrolled me and I was pretty hesitant. I was scared since I was a small scrawny child in a place full of Karate people. I went to my first class and I felt so welcomed by all the karate teachers. Sifu Tim is the most modest and Positive person. I am now 18, with a black belt. I learned so much from Sifu Tim. I leaned defense,Self-control, Respect. I was first a child who didn't have a will to live, I thought I had no talent. Sifu Tim showed me otherwise. Now I continue to be an Athelte and in hopes to be a professional fighter or other kind of athlete when I grow up. All thanks to Sifi Tim and his Family. I suggest going here! They treat you like family. read more

I went here last year and took part in the Keepin it Real class. Its a great class for exercise and learning self-defense. The experience I had was invaluable and Tammy and Sifu Tim were incredibly nice people. read more

My kids love this place. The staff is great and price is very reasonable. Anthony goes once a week and looks forward to going!

I feel so lucky to have found D-1. I love it! The Calvin's are amazing. Sifu Tim, Sifu Jarell and Sifu Isaiah are awesome instructors. I am at awe when I watch them with children. They really understand them and the kids are all smiles when they are there. My daughter loves it. I'm grateful that not only is she learning martial arts, but is learning about respect and is acquiring better listening skills. I started over a year ago and it has changed my life. They really break down the combinations we learn during class so you can understand them. Sifu Tim was in the Marines and was a Police Officer so he knows what will work and won't work in the real world. I can't wait to go class and feel great when I leave. The students there all work well together. We all have different goals and Sifu Tim helps us all accomplish them. I know it would be very difficult to find another place like this. It doesn't matter if you're a man, woman or child you will love this school and most importantly, learn how to defend yourself! read more

This place is too small for the amount of kids that go there. The student to teacher ratio is way too high. It also seems that they are only interested in having the kids bring in more kids or family and fiends. It's one big money grab to me , it should be about the kids but it's not. read more

This is seriously the best place ever! I couldn't be more happy with the program down there! The way they are with children, they make every person and child down there feel special! Everything is very family oriented. And I just cannot believe the results I've been seeing in my own child!! I would highly suggest D1 and only martial arts. 5 stars for sure!!! read more

I first met Sifu Tim and Tammy when we enrolled our daughter at Delta 1 when she was 4 years old. I was pleasantly surprised with the class. I found the environment very family oriented and non threatening. The staff at the school is very professional. They answered any and all question with regards to my daughter. They've also addressed any issues in a timely manner. Sifu Tim has very strong work ethics and he instills these beliefs in his staff and also in his teachings. Over the past 8 years, I've attended a few classes with Sifu Tim and have found his teaching very motivating for both me and my daughter. My daughter is now a black belt and is going for her second degree. We couldn't be any happier with the decision that we've made in regards to enrolling our daughter in this school. The friends that she's made while attending Delta 1 Martial Arts are friends that we not only associate while in school, but also outside of the karate school. The parents that we've met through our daughter are now our friends and now they'll be friends that we'll have for a very long time. I've seen these kids grow up with my daughter. I've grown to admire Tim and Tammy Calvin as owners and I'm honored to call them our friends. Keep up the great work.!! 2 thumbs up for Delta 1 Martial Arts. read more

I cannot say enough good things about D1. We definitely feel that we made the right decision in bringing our teenage daughter to this school. She learned discipline and developed focus from attending her classes, her new motto is "never give up." The best part is that Sifu Tim, Miss Tammy and all the instructors genuinely care about the character and moral development of their students. The instructors and students look after each other like family. I don't think we can find another martial arts school like D1 and Only, they truly live up to their name. read more

Beware of this place. I signed my son up for karate and due to my schedule and his lack of interest I notified them that I wanted to cancel. They said they needed 30 days so I didn't have any issue paying August. I was charged for September when we repeatedly told them please cancel. I have been going back and forth have had to cancel my card and disputed the charges and they say I owe for October. For a place that works off of referrals and word of mouth this is very poor service. I will never be going back and any of my sons friends ask about going to karate I will tell them do not go near this place. read more

I can't say enough good things about this place. They are great with kids and are always having special events for the children and adults. Very reasonably priced for the amount of time they put into teaching your kids. Tempted to takes classes myself, if only there were more time in a week. read more

We've been at D1 for a year and a half now. My son's first class, I was quite impressed. From the shaking of hands to how they earn their belts. He definitely enjoys being a part of this school and I've seen a different side to him. He, along with all students, receive honest constrictive criticism and honest feedback. Truly appreciate the whole team! Miss Tammy, Miss Vicki, sifu Tim, sifu Jarell and all black belt instructors...thanks!!! read more