Source: https://www.cmpb.gov.sg/before-ns/voluntary-early-enlistment-scheme/
All male Singaporeans and Permanent Residents will be enlisted
for full-time National Service (NS) at the earliest opportunity
upon turning 18. If you are at least 16.5 years old and wish to be
enlisted before turning 18, you may do so under the Voluntary Early
Enlistment Scheme (VEES). However, you will have to obtain your
parent(s)' or guardian(s)’ consent and be medically and physically
fit. You may have to go through an interview to ascertain whether
you will be able to cope with military training.
The VEES application process is as follows:
Each VEES application will be decided on a case-by-case
basis.
If you are no longer studying, or have just completed your GCE
‘O’ or ‘N’ Level but have no intention of furthering your studies,
you will receive a Further Reporting Order with details to report
for registration and medical screening. If we determine that you
are suitable to be enlisted before the age of 18 years, you will be
enlisted within four to six months after being given a definitive
Physical Employment Status, subject to training capacity.
If you have graduated from ‘A’ Level or diploma studies overseas
or are from a foreign school, you may have completed NS
registration and medical screening earlier. You will be enlisted
within four to six months after your course completion.