Abstract UN military observers patrol crisis areas in small teams. Their task is to determine whether seen military activity constitutes a violation to ceasefire agreements. Failing to see or establish a shared understanding of the activity can be damaging to the mission or put the teams in danger. We use ethnomethodology and conversation analysis to analyse how military observers verbalise and categorise military activity in ‘noticings’. The data are video recordings collected in car patrols in a training course. The analysis is based on fifty-three episodes of the patrols encountering unexpected military activity. The analysis focuses on the design features of and categorisation practices in noticing actions. It also shows how the noticings invite seeing the noticed feature from a particular perspective and in this way build a context for the joint and emergent activities of ‘monitoring’ and ‘observing’. The findings showcase how noticing actions and monitoring and observing are accomplished in interaction. They highlight the role of talk and embodiment as part of military observers’ professional competence and for maintaining situational awareness. The findings are relevant for and can be integrated in UN military observer training.