Introduction: When patients transition from long term care (LTC) to emergency departments (ED), communication among clinicians in different settings is often poor. We pilot tested a transfer form to facilitate communications of handover information among LTCs, emergency medical services (EMS), and EDs regarding LTC residents transitioning to and from the ED. We interpret implementation challenges in light of the “theoretical domains” implementation framework in order to produce lessons for future healthcare communication interventions. Methods: We provided setting specific training and a user guide to 13 participating sites, collected 90 forms to assess completion rates, and assessed perspectives on the form from 266 surveys of healthcare providers. Throughout the study, staff kept detailed notes on implementation of the form. We retrospectively categorized implementation challenges reported by survey respondents, and/or recorded in staff implementation notes, according to the theoretical domains framework. Results: The LTC patient transfer forms were used in 36.4% of transitions (90/247), and were completed most often by staff in the LTC (57/90, 63%). Survey results indicated that ED and EMS staff felt the information on the form was useful to them, although they rarely completed their sections of the form. Implementation challenges included low awareness/recognition of the form among healthcare providers, belief that the form distracted from patient care, lack of time for form completion, negative reinforcement for LTC staff (who saw little return for the time they invested in completing the form), and mistrust among clinicians who work in different settings. Conclusion: Future efforts to improve healthcare communications must be acceptable for all clinicians. Innovation should balance the workload required among sites/clinicians and the benefits that the intervention offers to sites/clinicians should be explicitly tracked and reported. For this intervention, more effort should be made to inform LTC sites that the transfer information they provide is useful for EMS and ED clinicians. Moreover, gaps in perspectives and lack of trust among clinicians who work in different settings must be recognized and addressed in any multi-site communication intervention.