Do voluntary National Insurance payments count as CSI?

No. You need CSI for the period you were a student or self-sufficient and you cannot make payments for past periods. 

However, if for instance, you were a student and also worked during your studies, you may be able to treat this as being a worker rather than a student. 

You can qualify as a ‘worker’ if the Home Office considers your work ‘genuine and effective’. This is a complex area of law and the nature of the work is assessed on a case by case basis. To give you a broad picture, a student working 20 hours a week at Sainsbury’s throughout her studies could apply as a worker, whereas the work of a student who only worked a couple of hours a month in the Students’ Union bar would likely not be considered to have been doing ‘genuine and effective’ work.

Note: this question, like other FAQs on Comprehensive Sickness Insurance (CSI), relates to applications for British citizenship, when considering whether periods of past residence were lawful. the3million’s Young Europeans have published a very useful document on key Citizenship facts which you can find here:

CSI is not required to apply for pre-settled or settled status under the EU Settlement Scheme. Also, once pre-settled or settled status has been granted, you are lawfully resident, and you do not need CSI.