They're drift dives in the sense that you don't have to swim back to an anchored boat. The dinghy comes to get you (hopefully) wherever you surface.Everyone keeps mentioning the currents? Are these drift dives? (Forgive me if that is a stupid question) Do you have to swim against the currents to do the dive? Or is it more like a seamount surrounded by currents and you just have to avoid them during the dive?
For the most part, you're hanging onto rocky reef during the dive, not swimming. However, kicking against current may be necessary when descending and finding a suitable viewing spot, though once you're on the reef, it's often easier to crawl from rock to rock unless the current is in your intended direction. Also, when a guide spots a whale shark, it's may be necessary (though entirely optional) to kick against current to get out into the "blue" and closer to the behemoth (it's amazing how camouflaged such a big fish can be - sometimes you don't see it until you're literally on top of it).