Does anybody know if the US Postal Service has instituted similar restrictions as Thailand and many other countries forbidding international mailing of phones with batteries?  

I want to purchase a phone from Amazon, have it delivered to my sister in the US, then have her mail it to me in Bangkok.  I'm not sure it's possible to do any more.

Phones with battery installed can be shipped internationally:

 

Quote

135.62 General

Only lithium cells and batteries under 135.63 and 135.64 that are properly installed in the equipment they are intended to operate may be sent internationally or to APO, FPO, or DPO locations when not restricted or prohibited by the destination country or APO, FPO, or DPO location. For specific country restrictions, see the applicable Individual Country Listing. For specific APO, FPO, or DPO restrictions, see the information for the destination ZIP Code in the article titled “Overseas Military/Diplomatic Mail” published in each issue of the Postal Bulletin.

Lithium batteries packed with equipment and lithium batteries sent separate from equipment are prohibited. Damaged or recalled batteries are prohibited and may not be mailed internationally under any circumstances.

source:http://pe.usps.com/text/imm/immc1_014.htm

Thanks, LM.  Good information.

135 Mailable Dangerous Goods

135.64 Lithium-ion or Lithium Polymer (Rechargeable) Cells and Batteries

Small consumer-type lithium-ion or lithium polymer (rechargeable) cells and batteries like those used to power cell phones and laptop computers are mailable in a single shipment with the following restrictions:

1. The batteries must be installed in the equipment they are intended to operate.
2. Each shipment may contain a maximum of four lithium cells or two lithium batteries.
3. The total Watt-hour rating (Wh) for each cell must not exceed 20 Wh per cell.
4. The total Wh for each battery must not exceed 100 Wh per battery.
5. Each battery must bear the Wh marking on the battery to determine if it is within the limits defined in 135.64c and 135.64d.
6. The batteries installed in the equipment must be protected from damage and short circuit.
7. The equipment must be equipped with an effective means of preventing it from inadvertently being turned on or activated.
8. The equipment must be contained in a strong, sealed package and cushioned to prevent movement or damage.
9. Mailpieces must not bear markings or labels identifying the contents as lithium batteries.