How is tax handled if I withdraw money from a pension account early?

According to the National Tax Service, non-pension withdrawals from a pension account are subject to a 15% withholding rate as other income.

This applies when contributions for which a tax credit was received and investment returns are withdrawn other than as a pension. If deferred retirement income (retirement pay transferred into the account) is withdrawn other than as a pension, it is taxed as retirement income, so check the expected tax with your financial company before withdrawing.