Loose coupling is a common way of organizing collaboration in work groups, but it has not been studied extensively in CSCW. In this paper, we consider the patterns of work that are seen in mobile groups that adopt a loosely coupled collaboration style. We report findings from interviews and fieldwork with teams of workers who deliver home healthcare services. In these teams, workers are mobile, widely dispersed, and autonomous, and team members communicate with each other only intermittently. Based on these findings, we identify and discuss four work patterns that occur in loosely coupled mobility: discretionary collaboration and effort thresholds, implicitly shared information, asynchronous communication and coordination, and barriers to synchrony. We consider the implications of these findings for the design of CSCW technologies. Categories and Subject Descriptors H.5.3 [Information Interfaces and Presentation]: Group and Organization Interfaces, Evaluation/methodology. General Term...