The International Gateway has the same hours as the main Epcot entrance. The only problem is that they do not start the security check until opening time. We came across this situation in June when we tried to get to Test Track at opening. There was already a long line at TT by the time we got there. In the past they used to let you through the turnstiles and held you back at a rope. This time everyone had to stay outside until opening time and then they started the security check. It was quite a mess with so many people lined up.