How do I Disable the swipe gesture of UIPageViewController?

The documented way to prevent the UIPageViewController from scrolling is to not assign the dataSource property. If you assign the data source it will move into 'gesture-based' navigation mode which is what you're trying to prevent.

Without a data source you manually provide view controllers when you want to with setViewControllers:direction:animated:completion method and it will move between view controllers on demand.

The above can be deduced from Apple's documentation of UIPageViewController (Overview, second paragraph):

To support gesture-based navigation, you must provide your view controllers using a data source object.

for (UIScrollView *view in self.pageViewController.view.subviews) {

    if ([view isKindOfClass:[UIScrollView class]]) {

        view.scrollEnabled = NO;
    }
}

I translate answer of user2159978 to Swift 5.1

func removeSwipeGesture(){
    for view in self.pageViewController!.view.subviews {
        if let subView = view as? UIScrollView {
            subView.isScrollEnabled = false
        }
    }
}