Objective: to describe patients' perceptions of communication technologies used in a nutrition service and to learn how they may contribute to the safety of postoperative bariatric surgery patients. Method: a descriptive and exploratory study with a qualitative approach was carried out with 12 postoperative bariatric surgery patients admitted into a teaching hospital in southern Brazil from March to July 2016, by means of a focus group (five meetings). Data analysis included text transcription and data were grouped by similarity and once more nominated as great units. Result: the following categories emerged from the analysis process: communication with nutritionists and patient safety; changes in eating habits and challenges; and weight loss and maintenance. The data showed that group appointments strengthen the relationship with nutritionists. Using several communication technologies promotes a sense of safety, because it facilitates access. Care guidelines reduce concerns associated with nutritional deficiencies and weight regain. Conclusion: the strengthening of the relationship with nutritionists associated with a wide range of communication technologies provide patient safety toward losing follow-up and having problems regarding nutritional deficiencies and weight regain.