The need for mental health services for older people living in rural areas is increasing in South Australia. Providing such care requires coordination between several types of services across government, hospital and non-government sectors. The purpose of this study was to identify barriers to collaboration from the perspective of external aged care agencies. A total of 42 responses from an online survey were qualitatively analysed. Four categories emerged, within which participants had identified barriers to collaboration: (1) awareness of services and certainty about responsibilities, in particular, a lack of awareness of which services are available; (2) referral criteria and processes, including the specific criteria needed to be eligible for these services; (3) opportunities to collaborate, with a perceived lack of formal opportunities for collaboration between individuals working across agencies; and (4) education of staff, with more joint education between agencies being recognised as having the potential to increase local knowledge and provide an opportunity for networking and relationship building, with greatest barriers experienced between mental health and social care services.