Background: In everyday conversations, a person with aphasia (PWA) compensates for their language impairment by relying on multimodal and material resources, as well as on their conversation partners. However, some social actions people perform in authentic interaction, proposing a joint future activity, for example, ordinarily rely on a speaker producing a multi-word utterance. Thus, the language impairment connected to aphasia may impede the production of such proposals, consequently hindering the participation of PWAs in the planning of future activities. Aims: To investigate (1) how people with post-stroke chronic aphasia construct proposals of joint future activities in everyday conversations compared with their familiar conversation partners (FCPs); and (2) how aphasia severity impacts on such proposals and their uptake. Methods & Procedures: Ten hours of video-recorded everyday conversations from seven persons with mild and severe aphasia of varying subtypes and their FCPs were explored using conversation analysis. We identified 59 instances where either party proposed a joint future activity and grouped such proposals according to their linguistic format and sequential position. Data are in Finnish. Outcomes & Results: People with mild aphasia made about the same number of proposals as their FCPs and used similar linguistic formats to their FCPs when proposing joint future activities. This included comparable patterns associated with producing a time reference, which was routinely used when a proposal initiated a planning activity. Mild aphasia manifested itself as within-turn word searches that were typically self-repaired. In contrast, people with severe aphasia made considerably fewer proposals compared with their FCPs, the proposal formats being linguistically unidentifiable. This resulted in delayed acknowledgement of the PWAs' talk as a proposal. Conclusions & Implications: Mild aphasia appears not to impede PWAs' ability to participate in the planning of joint future activities, whereas severe aphasia is a potential limitation. To address this possible participatory barrier, we discuss clinical implications for both therapist-led aphasia treatment and conversation partner training.