Hi,
When you reside abroad, you need to complete an application form (CF83) to apply to pay voluntary National Insurance contributions. This form can be found on the GOV.UK website by searching for NI38 which is a leaflet providing further information about paying voluntary National Insurance contributions abroad, the CF83 is at the back of the leaflet.
We can consider payment of voluntary National Insurance contributions as far back as 2006 to 2007 tax year but your application form would need to be received by us before 5 April 2023 to be considered that far back. If we receive the application form after 6 April 2023 we can consider payment of voluntary National Insurance contributions from 2017 to 2018 onwards.
Once we have received the application, then we would check if you were eligible to pay voluntary National Insurance contributions and we would issue a shortfall of years available to pay. We cant confirm how much this would be but current voluntary rates are £3.15 per week at the class 2 rate and £15.85 per week at the class 3 rate.
Guidance on social security abroad: NI38
Thank you.