Background The emergency medical service as a high-risk workplace is a danger to patient safety. A main factor for patient safety, but also at the same time a main factor for patient harm, is team communication. Team communication is multidimensional and occurs before, during, and after the patient’s treatment. Methods In an online based, anonymous and single-blinded study, medical and non-medical employees in the emergency medical services were asked about team communication, and communication errors. Results Seven hundred and fourteen medical and non-medical rescue workers from all over Germany took part. Among them, 72.0% had harmed at least one patient during their work. With imprecise communication, 81.7% rarely asked for clarification. Also, 66.3% saw leadership behavior as the cause of poor communication; 46.0% could not talk to their superiors about errors. Of note, 96.3% would like joint training of medical and non-medical employees in communication. Conclusion Deficits in team communication occur frequently in the rescue service. There is a clear need for uniform training in team and communication skills in all professions.