National Insurance Contributions are paid on employed and self-employed income earned above the NI threshold. Employees stop paying NI on their employed income once they reach State Pension age, even if they carry on working.
Self employed workers who reach State Pension age and pay Class 4 contributions will continue to do so until the end of the tax year.
Will I pay NICs on my pension if I retire early?
National Insurance is paid on employed and self-employed income, but not on payments from a pension scheme. This means that even if you retire before State Pension age and start drawing from a pension, you won't have to pay NICs on it. Do keep in mind that you may have to pay income tax on pension payments, though.