I moved to USA on a L1A Visa in June 2016 and my son moved as a full time student on F1 Visa in Aug 2016. Can I claim him as dependent, I pay all his expenses.

[bine22]

First, since you do meet the substantial presence test for 2016, you are a dual status alien. Turbotax does not support dual status returns (but if you are married you have other options)

A person on F1 is a nonresident alien for the first 5 calendar years. A nonresident alien cannot be claimed as a dependent (unless a resident of Mexico or Canada)

[Spiny-Norman]

Check this out. https://www.irs.gov/uac/who-can-i-claim-as-a-dependent Pretty easy to determine the rules form this