Introduction Breast cancer often leads to cancer-related cognitive impairment (CRCI), which includes both objective and subjective cognitive deficits. While psychosocial interventions benefit quality of life and distress reduction, their impact on cognitive deficits is uncertain. This study evaluates the integration of a cognitive module into a digital psychosocial intervention for breast cancer patients. Methods In this randomized controlled trial (RCT), 88 recently diagnosed breast cancer (BC) patients will receive the ICOnnecta't program (control group) – a digital stepped intervention addressing a variety of psychosocial needs. The experimental group ( n = 88) will receive ICOnnecta’t plus a cognitive module. Assessments at baseline, 3, 6, and 12 months will measure the interventions’ impact on cognition, emotional distress, medication adherence, quality of life, post-traumatic stress, work functioning and healthcare experience. Feasibility and cost-utility analyses will also be conducted. Results The cognitive module includes three levels. The first level contains a cognitive screening using FACT-Cog Perceived Cognitive Impairment (PCI). Patients with PCI <54 progress to a cognitive psychoeducational campus (Level 2) with content on cognitive education, behavioural strategies and mindfulness. Patients with persistent or worsened PCI (≥6) after 3 months move to Level 3, an online cognitive training through CogniFit software delivered twice a week over 12 weeks. Conclusions This study assesses whether integrating a cognitive module into a digital psychosocial intervention improves objective and subjective cognition in breast cancer patients. Secondary outcomes explore cognitive improvement's impact on psychosocial variables. The research will contribute to testing efficacious approaches for detecting and addressing cognitive dysfunction in breast cancer patients. Trial registration ClinicalTrials.gov, NCT06103318. Registered 26 October 2023, https://classic.clinicaltrials.gov/ct2/show/NCT06103318?term=serra-blasco&draw=2&rank=4