[FARS]

For a long time he traveled on his mother's passport and she added Abdullah to his name when she took him off hers. Somewhere on AntiMullah there is the full name on his first passport and certainly on FR in articles on the subject. Amazingly (or not) his mother's passport renewal records have since disappeared.

[trumandogz]

I just a little younger than Obama traveled extensively as a child. From the time I was born to the time I was four or five I traveled on mom’s passport and after that I had my own US Passport.

So, doubt that Obama during that very same time period could have traveled on his mom’s passport and must have gotten his very own passport sometime when he was four or five.