I will be on a layover in SIN and will be staying in the transit area. I am bringing a couple of small packages (less than 2kg each) that I want to get to my friend who lives in Singapore. So I figured I would just mail them from the airport while I am there. On the Singapore Post website, it shows locations in the transit area. My questions are:

- If I mail them from the transit area (i.e. airside) to an address in Singapore, do I need to do a customs declaration of some kind? After all, the goods are entering the Singapore via the mail, right?

- Can the Mobile Post Offices take a small package of less than 2kg?

- Do the post offices take a credit card for payment, or only SGD cash?

FYI, here are the locations listed on the Singapore post website.

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Changi Airport Terminal 2 – Transit Daily 6.00 am - 10.30pm
Transfer F (near "Perfumes and Cosmetics")
Airport Boulevard
Singapore 819843

Mobile Post Office (Post-On-Wheels) Daily 6.00am - 10.30pm
Terminal 1 Transit Area

Mobile Post Office (Post-On-Wheels) Daily 6.00am - Midnight
Terminal 3 Transit Area