Background: Flexible pes planus (flat feet) in children is a common reason parents and caregivers seek health professionals consult and a frequent reason podiatrists prescribe foot orthoses. Yet no universal agreement exists on the diagnosis of this condition, or when and how foot orthoses should be prescribed. The aim of this study was to garner consensus and agreement among podiatrists on the use of FOs for paediatric flexible pes planus. Methods: A three round Delphi consensus survey was undertaken with 15 podiatry experts from Australia, New Zealand and the United Kingdom. Round one gathered consensus on the diagnosis and intervention into paediatric pes planus with specific questions on types of FOs and prescription variables used. Round two and three were based on answers from Round one and gathered agreement (rationale for choices) on a five point Likert scale. 70% of respondents had to agree to a statement for it to be accepted as consensus or agreement. Results: Consensus and agreement was achieved for 83 statements directing the diagnosis of pes planus (using FPI-6 and/or rearfoot measures), common signs and symptoms (e.g. pain, fatigue, abnormal gait and other functional concerns) that direct when to intervene into paediatric flexible pes planus. Prefabricated orthoses were the preferred intervention where adequate control is gained with their use. When customised orthoses are prescribed, a vertical [heel] cast pour (71.4%) and minimal arch fill (76.9%) are the prescription variables of choice, plus or minus additional variables (i.e. medial heel (Kirby) skive, the use of a University of California Biomechanical Laboratory device or a medial flange) dependent on level of disorder and plane of excessive motion. Conclusions: This study identified consensus and agreement on a series of diagnosis methods and interventions for the paediatric flexible pes planus. A clinical protocol was developed from the resultant consensus statements which provides clinicians with a series of evidenced-informed statements to better guide them on the when, how and why FOs are used specific to this population.