Poser
WKR
Surfing is one of the things I do to stay fit and enjoy life. Takes an ocean, though, so I would guess swimming could be good too. But I cannot imagine a method of swimming that keeps the heart rate or intensity I achieve for long periods while surfing. Even if there is a way, can't imagine doing it voluntarily, whereas while surfing we tend to be anxious to utterly tax our upper body and cardio.
Paddling out on a surfboard can be tough, especially against the tide and with lateral currents as You’re definitely at a mechanical disadvantage, not to mention dealing with breaking waves. I don’t live anywhere near the ocean (people do river surf around here during the spring melt off), but I do go on a surf trip every so often with a group of friends and it can be a total ass kicker certain years. Like anything else, you adapt to it and get good at it if you do it enough, but it can be so frustrating and physical fighting harsh conditions
I’d also add that “surfing”, much like “skiing” can mean a wide range of things depending on how, when and where you do it. Could be the most mellow, relaxed thing ever, or could be the most intense and surreal life experience you’ll ever have. Certainly, though, you need to be some kind of reasonably good swimmer in order to be a surfer.