How to find someone's prisoner number
The short answer
Everyone gets a prisoner number when they arrive in prison. The simplest way to get it is to ask them when they first call you. If that doesn't happen, their solicitor or the Prisoners' Families Helpline can help you work out what to do next.
Why you need it
You will need the prisoner number to:
- Write to them: the number goes on the envelope
- Send them money: you can send money online on GOV.UK, and you also need their date of birth
- Add them as a contact on services like Purple Post
How to get it
- Ask them on their first call. Calls usually happen within 24 hours of arriving, but can take up to 72 hours. Keep a pen nearby and write the number down.
- Ask their solicitor, if they have one. After a court sentence, you can also ask the court cells where they have been taken.
- Call the Prisoners' Families Helpline on 0808 808 2003 (Monday to Friday 9am to 8pm and weekends 10am to 3pm). It is free and confidential.
If you don't know which prison they are in
Use the Find a Prisoner service if they are in England or Wales and you haven't heard from them after 72 hours. You will need their name, and their date of birth or age if you know it.
- They must give permission for their location to be shared, and they can refuse.
- You should get a reply within 4 weeks.
- The service does not give information by phone.
- The service is for finding which prison someone is in. Don't rely on it to give you their number.
If they have been moved
Write to their previous prison, and your letter should be passed on.
Get started with Purple Post
Available at HMP Parc, HMP Five Wells and HMP Rye Hill. If your loved one is at another prison, register your interest.
Last checked: 8 November 2026. Rules and prices can change, so please check with the prison or provider.