This is a well known fact to everybody. We cannot float in air, and we can do it in water when we swimm. Huge ocean ships float. Unless something breaks their shape, they do not sink.
Submarines float in ocean, easily changing their depth.
A special simulator was constructed by NASA experts to prepare the crew to perform various activities and function in the state of weightlessness in space. In the pool, the future astronauts could move heavy large equipment and at themselves in their massive space-suits. Normally, outside the water people could not move so heavy stuff and manipulate it, in the water they can. Things, when submerged in water, are easier to support by the same amount, the water they displace weighs. The KIE Group.