At one juncture at least, they are saying as a Senator he was able to get a passport and circumvent the rules of obtaining a passport. As to the other times, he went out of the country, I would not know. This is discussed in the other many threads.
One theory is that, into the 1980s at least, he still held an Indonesian passport. That would account for how he was able, in college, to visit Pakistan with a roomate...even while the US didn’t have diplomatic relations with Pakistan at the time.