Hi I am looking to start an international business to import a few things, clothing from Bangkok to Australia. Does anyone know of a good postal service/place around Pratunam/Sukamvit area or close by???
I will need to post a few boxes.

DHL comes to mind. However, cheap they are not!

There are shippers in the Pratunam area. They ship freight by sea. On the back sois not far from the First Hotel on Phetchaburi Road are some places you can check out. Sample shipper:
• Boss Air-sea Cargo Company • Ratchathewi, bangkok • Cargo, Packing And Crating

Back 10 or 12 years ago I used a hotel in this area a few times called the Opera Hotel There were several of these shippers near by. Think the Opera is torn down or something else now - couldn't find it a year ago with a quick look. (Old link for that hotel showing address.)
SoiDB - Opera Hotel [Bangkok - Hotel]

If everything is in small packages, and legal, you can also use the Thai Post Office. They are very reliable and not that expensive if you don't mind a little wait.

There are many wholesalers in the Pratunam area not far from Baiyoke Sky Hotel They will tell you how to ship things. Wholesalers near this Krung Thong Plaza.
http://www.krungthong-plaza.com/index_eng.php

Bobae Market is another place to check out. This link mentions shipping agents.
Bobae Market - Clothing Wholesale


Happy New Year.

On the few occasions I've sent items back from Thailand (such as winter clothes from prior northern hemisphere travel or all the cruddy souvenirs I've collected) I've used the standard Thai post office and the service and price has been just fine. Perhaps if you want to regularly send back items, though, then contacting a private shipper might be a better way, as Koonel says. Then you can try to negotiate a discount for regular use.

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