We have flown UA between the U.S. and South America, and got club access at the initial airport (e.g., LAX) as well as the last airport before going overseas (e.g., EWR or IAH), but in those cases the international leg was clearly marked BusinessFirst. I did finally get through to UA by phone and rep said it would be BF, and we'd have access, but I'll bank on just EWR for sure. I have 2 free passes through my UA Explorer Visa card, but can find just one.