Two pictures of beaches from Flickr user litrate, with no clear identifying tags. Here's the first one, which I suspect is Horgabost (or near to there) on the west coast of Harris, as that's Luskentyre over the water:
This next one, hmmm not sure but think it is a few miles to the south. It looks like the one the bus stops at (if running ahead of schedule) for a few minutes to allow people to have a quick stroll on the beach. (Not quite the bus service you get on the mainland):
Anyone out there want to clarify which beaches these are?