Background: Communication in the intensive care unit is challenged by patients’ inability to speak owing to intubation, treatment, and illness. Research has focused on the use of communication tools or techniques, characteristics of the communication between patients and clinicians, and their experiences of communication challenges. However, few studies have combined the perspectives of patients, family members, and clinicians. We explored communication from different angles and investigated challenges that cannot be explained by ineffective use of aids and communication techniques. Objectives: The aim of this study was to explore communication between patients, family members, and nurses and to investigate previously unidentified communication challenges. Methods: This study used a case-oriented design with multiple triangulations. It was conducted in two general intensive care units at a Norwegian university hospital. Participant observations were conducted on nine mechanically ventilated patients while communicating with family members and healthcare personnel. Following the observations, individual interviews were conducted with six patients, six family members, and nine healthcare personnel. Findings: Communication often seemed uncomplicated at the time of observations, but information from the interviews revealed another picture. We demonstrate what participants emphasised differently when they discussed their experiences, revealing a discrepancy in perceived importance in the situation. Family members had an important role in interpreting signs from the patient, uncovering challenges that would have been unknown to the nurses otherwise. Conclusions: This study illustrates how communication challenges in the intensive care unit may not be perceptible to an observer or to all of the participants involved at the time of the communication. Nurses need to be aware of these communication challenges and realise that the patient might face issues that cannot be easily solved without extensive involvement of the patient, family, and nurses, and perhaps not even until a later stage in the patient's recovery process.