To describe participants' experiences of being treated for peri-implant mucositis. A qualitative study with nine individual, semistructured interviews was performed. The interview guide was based on a focus group interview. The participants had recently been treated for peri-implant mucositis on one dental implant in a randomised controlled trial (RCT). The treatment included information, oral hygiene instructions, nonsurgical treatment with Er:YAG laser or ultrasonic scaler and professional cleaning in several sessions over 6 months. The interviews performed were analysed using qualitative manifest and latent content analysis. The manifest results showed that learning how to brush the teeth, and repeated feedback, was appreciated, and increased the motivation to improve oral hygiene habits. Most participants experienced no discomfort from the treatment. The participants had an understanding that a longer treatment time was required to ensure the quality of the treatment. Respect and attention were important elements of the personal treatment. The latent results suggest that treatment with a laser or an ultrasonic scaler was not perceived as the most important part of the treatment. Participants felt that receiving information about the treatment process was more important; moreover, a person-centred approach gave a feeling of good and safe care. The present study highlights factors of importance in treatment of peri-implant mucositis with laser and ultrasonic scaler. A person-centred approach with respect and attention is important for a good and safe experience and may be important factors in future treatments.