Concerning GST filing and payment, the Statutory compliance Requirements for Singapore  GST registered companies are: GST return to IRAS must be submitted within a month from the end of each prescribed accounting period. The accounting period is determined quarterly. Both the output tax and input tax must be filed in your GST return and the difference between output tax and input tax is the net GST that is either payable to IRAS or refundable to you by IRAS. If you are on a GIRO plan for GST payment, GIRO deductions are on the 15th day of the month after the payment due date. Without a GIRO plan, GST filing and payment must be done within a month from the end of the quarterly accounting period. If a special GST accounting period applies in your case, the return submission deadline is one month from the last date of the special accounting period. Systems must be established by GST registered companies to track their transactions, and effectively plan and utilize their available resources to submit their GST returns on time. GST filing is done online and businesses can e-file GST F5 one day after the accounting period ends.