Aim: The overall aim was to describe and compare pathways for older patients and the involved actors’ experiences of decision-making in acute situations in ambulatory care. Methods: The overall three-fold design, comprising exploratory, descriptive as well as comparative ones, was conducted inductively, including a mixed method with a convergent integrated approach to empirical data. The four involved studies were analysed using either quantitative or qualitative analysis methods. Results: Most older patients’ pathways when being assessed by ambulance personnel involved receiving care at hospitals. However, an increasing trend of non-conveyance to hospitals was identified during a five-year period (2014–2018), which means receiving care, for example, at home or primary healthcare (PHC) centres. Decision-making about the level-of-care for older patients was more or less uncertain for all involved actors, i.e. older patients, significant others and healthcare professionals such as ambulance personnel, registered nurses, specialists in general practice at PHC centres and community health nurses. To increase the level of certainty in the decision-making process, all actors was supported by both an individual and external dialogue. Individual dialogue gave support by using own experience and knowledge. For ambulance personnel and community health nurses, support was also partially gained from decision support tools but was regarded as insufficient when older patients had non-specific symptoms. External dialogue provided support through mutuality, and via collaboration, a common goal, trust and responsibility. Mutuality gave support through experience and knowledge being shared with all involved actors, which provided a common comprehensive understanding that facilitated consensus in the decision-making. Conclusion: The increasing level of non-conveyance to hospitals and uncertainty during decision-making highlights the need to develop and extend the availability of dialogue-based collaborations as support in ambulatory care. Dialogue-based support involves all actors contributing to the decision-making. Healthcare professionals need to be aware of the prerequisites and the support that mutuality in external dialogues brings. Healthcare organisations need to develop and extend dialogue-based collaboration in ambulatory care by combining different expertise and providing conditions to increase support in decisions adapted to older patients' needs.