BackgroundTo the best of our knowledge, although ageing-induced fatigue could cause adverse outcomes such as frailty, there is currently no intervention for it. This study evaluated the effects of an individualised exercise programme with/without BCE strategies on reducing fatigue in older adults.MethodsA three-armed cluster-randomised controlled trial (RCT) was conducted with 184 participants (mean age: 79.1 ± 6.4; mean frailty score: 2.8 + 0.8) from 21 community centres (ClinicalTrials.gov: NCT03394495). They were randomised into either: the COMB group (n= 64), receiving 16 weeks of exercise training plus the BCE programme; the EXER group (n= 65), receiving exercise training and health talks; or the control group (n= 55), receiving only health talks. Fatigue was assessed using the Multi-dimensional Fatigue Inventory (range: 20 to 100, with higher scores indicating higher fatigue levels) at baseline, and immediately, 6 months, and 12 months post-intervention.ResultsThe GEE analyses showed significant interaction (time x group) between the COMB and control groups immediately (p< 0.001), 6 months (p< 0.001), and 12 months (p< 0.001) post-intervention. Comparing the COMB and EXER groups, there was a significant interaction immediately (p= 0.013) and at 12 months post-intervention (p= 0.007). However, no significant difference was seen between the EXER group and control group at any time point.ConclusionsThe COMB intervention showed better immediate and sustainable effects (i.e., 12 months after the intervention) on reducing fatigue in frail older adults than exercise training or health education alone.Trial registrationClinicalTrials.gov (NCT03394495), registered on 09/01/2018.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12877-023-04080-0.