I made online purchases with a total value of more than S$400. These items will be delivered to me in Singapore via a courier service provider. Is there any tax payable?

For goods imported by courier service, the prevailing Goods and Services Tax (GST) rate is calculated based on the total Cost, Insurance and Freight (CIF) value of the goods. However, GST relief is granted for goods of a total value not exceeding S$400 if they are imported by air freight or parcel post.
There is no GST relief for goods imported by courier service via sea freight and land unless otherwise specified here.
You may wish to clarify with your courier service provider on the mode of delivery for your parcel(s) if it is not agreed upon in the terms of service.
You may also wish to check with your courier service provider on their services rendered (i.e. customs clearance and documentation) and the corresponding service fees that apply.
For goods that had been imported as parcel post, please click here for more information.
Should your goods be controlled, please liaise with the specific Competent Authorities (CA)s on their licensing requirements. You may refer to the HS/CA Product Code Checker to determine if your goods are controlled.