I have been in the US since July 2007. Initially I was on F-1 visa. I am a H1B visa holder since October, 2009. My first 3 year period on H1-B will be ending September 2012. My company is planning to send me to work in Thailand on their behalf for a period of one year. I will be going to Thailand on a business visa. Thailand is not my home country, I am an Indian citizen. My payroll will be in the US with my US company. My US based company plans to file for my H1-B extension in June 2011 before my H1-B expires.

Following are my questions:

1. Should I be considered as a resident alien for my 2011 taxes or will I be considered as non-resident alien?

2. Even if I get my H1-B extension, my visa will not be stamped. Does the visa stamping have an effect on whether I am considered a resident alien for tax purposes ?

3. If I file my taxes as a US resident alien, do I need to file taxes in Thailand.

4. If I am to file my taxes for 2011 as dual status, do I need to file taxes in Thailand ? Do I need to pay social security and medicare beyond September 2011.

Any help to clarify my situation would be greatly appreciated.

If you were in U.S. in 2010 and 2011, you are resident for 2010 and 2011. It does not matter if H1-B is stamped or not.
If you do not meet substantial presence test in 2012, you are nonresident after you left U.S. Any income earned while you are not resident of U.S. is not taxable in U.S. Your U.S. Tax Return: Substantial Presence Test

Thank you for a quick reply, but I meant to ask those questions for this year i.e 2012 and not 2011, sorry for the confusion. I will re-phrase the questions with the correct year. I have been in the US for more than 31 days in 2012 and more than 183 days in the past 3 years, so I pass the substantial presence test. But will I not be considered non-resident once my H1-B expires in September ?

1. Should I be considered as a resident alien for my 2012 taxes or will I be considered as non-resident alien?

2. Even if I get my H1-B extension, my visa will not be stamped. Does the visa stamping have an effect on whether I am considered a resident alien for tax purposes ?

3. If I file my taxes as a US resident alien, do I need to file taxes in Thailand.

4. If I am to file my taxes for 2012 as dual status, do I need to file taxes in Thailand ? Do I need to pay social security and medicare beyond September 2012.

Sorry again, could you please answer these questions with respect to 2012.

You are resident for 2012. After you leave U.S. you are dual status but your default residency termination date is Dec 31, 2012 so you will pay US taxes up to that date.