Singapore doesn’t deduct taxes directly from employees’ pay checks, i.e. Singapore does not have payroll withholding taxes.
When a non-Singaporean employee stops working in Singapore, gets sent overseas, or leaves the country for more than three months, the employer must:
Tell the Singapore tax authorities about the employee’s departure as soon as they know.
Hold back any money owed to the employee until the tax authorities give tax clearance—unless the employer is fully covering the employee’s Singapore taxes.
The notification must be made no later than one month prior to the date of cessation/departure, or two months from the date of cessation/departure where the employer is bearing full Singapore taxes for the employee.
Non-Singapore employees are also subject to tax on unexercised/unvested stock options/awards on a deemed gain basis when they cease employment or leave Singapore.
As a concession, tax clearance need not be obtained in certain scenarios.