Please note that MYJAPAN will not charge any Singapore custom GST.
Custom GST will only be noted by Singapore government.
and customer is responsible for the payment if it meets.
You may refer here to check how to calculate custom GST.
You can refer to Customs website at www.customs.gov.sg for any updates and information on dutiable and prohibited items.
Any dutiable items imported into Singapore are subject to Customs duty and/or Excise duty in accordance with the Schedule to the Singapore Customs Duties Order.