A person who uses a snorkel to do snorkelling.(noun)
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Use "snorkeller" in a sentence
"Whether snorkeller or diver, the attraction is the same: female southern stingrays, which glide silently through on soft, broad "wings" in search of a morsel of squid, and leave behind a lasting impression."
"Now I'm not a confident snorkeller, in fact I haven't donned the gear since I was about ten so my autonomic nervous system much prefers to breath through its nose, indeed feels compelled to do so even when it knows it mustn't."
"Teenagers will walk to the edge of the ocean, attention glued to their phones even as they're slipping their fins on, says veteran snorkeller and diver John Hessburg."