Yes, I wear a full immersion suit for winter or cold water overwater flying. As such flying for me is usually a search, I don't carry anyone else with me. Ironically, some of these suits though excellent flotation aides, are not qualified as lifejackets. This has created a regulatory dilemma, as Transport Canada proposed to require wearing a lifejacket over the immersion suit for over [cold] water flying. This proposal was introduced to a committee meeting I was attending many decades ago. The TC staff member presenting the proposal had not considered that the combination of an immersion suit, and lifejacket could result in being too buoyant to egress a sinking aircraft. TC conceded this point, and I think that the status quo was allowed to remain. The aircraft must carry inflatable lifejackets, but if the occupant is wearing an approved immersion suit they don't need to also wear the lifejacket. I had pointed out that while wearing an immersion suit, it might be difficult to don and later inflate a life jacket with the lessened mobility while wearing an immersion suit.
Happily, the occasions of ending up in the water while flying are low, but the criticality if it happens is high. Conditions which could be a nuisance to a healthy swimmer, could be fatal for an injured person in the water who can no longer swim. I can briefly remember being in the water, holding on to the wing, calling out for my fellow pilot, as I could not see him. I wanted to assure he was okay, and had inflated his lifejacket. But, I had no idea how badly injured I was, and I could not even manage to "jerk to inflate" my lifejacket, I had to mouth inflate it. I wasn't going to be able to help him. The crash was right in the floatplane bay of a water aerodrome, and witnessed, so rescue was swift. That made the difference, as I would not have lasted in the water.