I get this question a lot from new students and their parents. The short answer is Karate is a contact activity, but we don't do full contact fighting. The actual level of contact depends on the age, level, and health of the participant.
All ages and levels: We do partner exercises which may involve grappling, escaping, throwing, breakfalls, joint locks, and blocking attacks.
Kids (under 12 yrs) and White Belts (any age): These students should not be making contact with each other with strikes (punches or kicks).
Adults/Teens: We gradually introduce body contact, particularly to the abdomen. Students must learn how to receive a hit. This is a vital part of developing the resiliency necessary to carry on in a self defence situation. Students participate in strength training and body hardening exercises that gradually make this a much less difficult task.
My answer to anyone wondering why we don't do full contact fighting is this: The cost/benefit relationship of engaging in this level of contact does not make sense for most students. The risk of injury in striking sports is very high, especially concussions and brain trauma. There is no protective equipment on the market that prevents concussions, and studies have shown that concussions occur from *both* contact to the head and the body. The wear and tear on the body is excessive and almost always results in a shortened training career. I encourage lifelong activity and sport, and have found that moderation is key to prolonged participation and enjoyment of Karate.