Background: Leisure time for adults with learning disabilities is often diversionary and spent doing passive, solitary or family-orientated activities. Befriending, as a hybrid "natural" support, may help adults with learning disabilities overcome the barriers to participation in nonsegregated leisure. Materials and methods: Four case studies of pairs of "befrienders" and "befriendees" were recruited purposively. Participant observation was carried out with each case, followed by semi-structured interviews with participants and relevant stakeholders. Data were analysed using thematic analysis. Results: Befriending activities were mostly limited to enjoyable yet "casual" leisure activities that adults with learning disabilities might already participate in with family and paid service providers. Negotiating the befriender role between friend and professional was an ongoing challenge. Conclusions: Outcomes of leisure-befriending relationships for adults with learning disabilities are linked to both the nature of relationships and the types of activities undertaken. There are four proposed ideal types of leisure-befriending relationship, yet repeating familiar "casual" leisure activities means adults with learning disabilities risk missing out on novel leisure and social experiences.