If you don’t have insurance but were not at fault for the accident, you can file a claim with the other party’s insurer.
Keep in mind, however, that the other party’s insurance company does not represent you. While your own insurer must act in good faith in regard to your claim, the other party’s insurer has no such obligation. They can simply ignore you.
For this reason, we recommend contacting an experienced California accident lawyer before making a claim directly against another party’s insurance.