I thought it was a topic worth exploring again.
Second Life offers opportunities to do some snorkelling. Clearly, the naturist snorkelling at Naked Dreams (see photos below) are away and far our favourite spot, but a search will turn up several locations in which to do it. The Marketplace also has many snorkelling or diving accessories, a range to meet everyone’s pocket, and the set I’m wearing in the photos (below) cost L$5 from the marketplace, although there’s a free set at the embarkation point at Naked Dreams.
I’ve snorkelled, without much success, I can never get my breathing right, and never scuba dived, but I think that SL scuba might be a reasonable visual representation of the RL variety.