IntroductionPrehabilitation in colorectal surgery is evolving and may minimise postoperative morbidity and mortality. With many different healthcare professionals contributing to the prehabilitation literature, there is significant variation in reported primary endpoints that restricts comparison. In addition, there has been limited work on patient-related outcome measures suggesting that patients with colorectal cancer needs and issues are being overlooked. The Defining Standards in Colorectal Optimisation Study aims to achieve international consensus from all stakeholders on key standards to provide a framework for reporting future prehabilitation research.Methods and analysisA systematic review will identify key standards reported in trials of prehabilitation in colorectal surgery. Standards that are important to patients will be identified by a patient and public involvement (PPI) event. The longlist of standards generated from the systematic review and PPI event will be used to develop a three-round online Delphi process. This will engage all stakeholders (healthcare professionals and patients) both nationally and internationally. The results of the Delphi will be followed by a face-to-face interactive consensus meeting that will define the final standards for prehabilitation for elective colorectal surgery.Ethics and disseminationThe University of Glasgow College of Medical, Veterinary and Life Sciences Ethics Committee has approved this protocol, which is registered as a study (200190120) with the Core Outcome Measures in Effectiveness Trials Initiative. Publication of the standards developed by all stakeholders will increase the potential for comparative research that advances understanding of the clinical application of prehabilitation.PROSPERO registration numberCRD42019120381.