Objective: The ED at the National Referral Hospital in Honiara, Solomon Islands, receives approximately 50 000 patients per year. A 2014 review of ED functioning identified deficiencies in triage processes. Placement of Australian volunteer advisors provided an opportunity to develop and implement a purpose-designed triage system. Methods: Action research methodology and the ‘plan, act, observe, reflect’ cycle was employed, leading to the development of a three-tier triage system based on the South African Triage Scale. ED patient flow and data management processes were simultaneously updated, and staff were trained in the new system. After a pilot period, the Solomon Islands Triage Scale was implemented in August 2017. Evaluation after 3 months of operation included predictive validity (using admission and case fatality rates as surrogate markers of urgency) and reliability (based on inter-rater agreement at retrospective chart review by an independent nurse). Results: In the period 1 August to 31 October, there were 10 905 presentations, of which 97.1% were allocated a triage category (1% category 1, 21.3% category 2 and the remainder category 3). Admission rates correlated closely with triage category (P < 0.01). The case fatality rate was 22.1% for category 1 patients, 0.09% for category 2 and 0.01% for category 3 (P < 0.01). An audit of 96 records conducted in October 2017 revealed 88.4% agreement for triage category allocation. Conclusion: Solomon Islands Triage Scale is the first three-tier triage scale to be implemented in the Pacific region and appears to have adequate validity and reliability. The partnership between Australian volunteers and local clinicians is a positive example of capacity development and represents a model that could be implemented in other resource-limited settings.