Of course cheetahs can swim. All cats, domestic, feral and wild can swim well. As is the case for all cats, it is as if cheetahs are born with firmware in their brains, to use the language of technology, which gives them competent swimming skills at birth. Some species can swim better or more confidently than others because they sometimes hunt where there is water such as swamps and rivers and the tiger and jaguar are two excellent examples. Both these species love the water. The tiger is a particularly strong swimmer with excellent stamina. You’ll see plenty of pictures of them hunting in and around water and references to their swimming prowess in the books. Tigers even swim in the open sea.

In contrast, the cheetah does all its hunting on open or semi-open landscapes as it needs to use it’s colossal speed to achieve success. Therefore you will not see a reference in the best wild cat books on cheetahs swimming when hunting or how good or bad they are at it.
They will swim when they have to such as crossing a river. The picture on this page is a classic example but by the look of their expressions they dislike it as much as a lot of domestic cats.
The video shows cheetah cubs very cautiously following their mother across a small pond:
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They swim like any other cat, small or big. As I said, cheetahs are competent swimmers like all other healthy cats of any species.