The study is designed to determine glycaemic control achieved using the FreeStyle Libre Flash Glucose Monitoring System (FreeStyle Libre) versus Self-Monitoring Blood Glucose (SMBG) for the self-management of diabetes.

Inclusion Criteria:

• Aged ≥4 years and ≤17 years.
• Has an identified Caregiver of ≥18 years.
• Type 1 diabetes using insulin (administered by injections or CSII) for at least 1 year.
• Current insulin regimen has been unchanged for at least 2 months prior to enrolment (e.g. change of insulin or administration method), with no plans to change insulin regimen.
• Currently testing BG, on average at least 2 times per day.

Exclusion Criteria:

• Concomitant disease or condition that may compromise patient safety including and not limited to; cystic fibrosis, severe mental illness, known or suspected eating disorder or any uncontrolled long term medical condition.
• Currently prescribed oral steroid therapy for any acute or chronic condition (or requires it during the study).
• Currently receiving dialysis treatment or planning to receive dialysis during the study.
• Female participant known to be pregnant.
• Participating in another device or drug study that could affect glucose measurements or glucose management.
• Currently using or planning to use FreeStyle Libre Flash Glucose Monitoring System or a Continuous Glucose Monitoring (CGM) device during the study.
• Has used the FreeStyle Libre Flash Glucose Monitoring System or a Continuous Glucose Monitoring (CGM) device in the previous 3 months.
• Known (or suspected) allergy to medical grade adhesives.
• In the investigator's opinion the participant is unsuitable to participate due to any other cause/reason (participant and caregiver considered).