How does a Hermit Crab swim?

It depends. If it is a land hermit crab "no", you do not want to put it in deep water to make it swim, it can actually just drown and die. I used to have a hermit crab and my friends babysitted it and when i got back the water bowl was spilt and my hermit crab was laying on its side, dead. If it is a water hermit crab, "yes". It needs water so it can swim, and just relax in it. it needs it!