Background: Individuals with intellectual disabilities are amongst the groups most vulnerable to sexual crimes. However, their limited cognitive abilities can make it challenging to obtain detailed statements from victims during investigative interviews. This study examined whether practising answering open-ended questions early in the interview increases the accuracy and abundance of incident-related information provided by individuals with intellectual disability. Method: Forty-eight adults with intellectual disabilities and 32 children without disabilities aged 5-7 were interviewed about a photography event. Results: When practising with open-ended questions, adults with intellectual disability and children without disabilities gave greater detail than those whose practise narrative involved specific questions. Furthermore, both groups provided more information in response to open-ended questions. No effects were observed for inaccurate details. Conclusion: Narrative practices could afford individuals with intellectual disability the opportunity to familiarise themselves with open-ended prompts, enabling them to provide more information during the substantive phase of the interview.