I just got a 17 week old Newfie and have an interest in getting him his Water Dog certs. Suggestions on the age to start him swimming? I'll check the NorCal Newf Club for some info, but figured I might get some helpful suggestions here too.
Our pup (who was born in late April so the weather was nice and the water was warm) was introduced to swimming before we brought him home at 10 weeks. I think the important thing is that the water is warm because puppies can't regulate their body temperature as well as a grown dog. If you have a kids paddling pool that would probably be a good place to start getting him used to water.
I'm sure someone with more experience with water breeds will pipe in.
This is how I did it, I'm not sure how "right" it is. Make the water fun. I started in the tub. Without puppy there, run the water until it's warm then plug the drain and only fill the tub a little bit, like an inch or two, so there is still a dry end. Bring in the puppy and place him on the dry end. Give him treats for being there, encourage him to step in the water by luring him forward. Splash the water a little, rub it on his legs and belly, just make it a fun game! Put a tennis ball or favorite toy in the water and drag it around. Get him to play in it.
When you actually have him swim, I agree warm water is better but I know that may not be possible. Have him on leash and go into the water. Do NOT drag him in or force him. If he stops, you stop. Take a step toward him and kneel down to encourage him to come to you. Be excited and use favorite treats to lure him in, or a favorite toy. Let him get the treats/toys for following you, don't just lure and tease him. Reward the progress. Run back and forth into the water and back out again. Baby steps! It should all be a game. He might be naturally willing to follow you even to the point where he swims. If so that's awesome!! If he won't go in so far as to swim, try this. Once he'll enter the water carry him out to where he can't stand up. Keep your hands under him to support him and lower him down. If he freaks out when you pick him up and carry him then just stop. Put him down on dry land. You don't want the experience to be scary at all. Go back to working on luring and playing games to try to get him interested. Anyway, he should be fully supported in your hands when you carry him out, lower him to just let his feet touch the water for a second then lift him back up. Lower him again until his elbows/knees are in and let him doggy paddle while you support him. This is important so they can find their swimming legs. Doggy paddling is natural but if you just drop him in he will panic and may freeze and sink. Not a good experience. Your hands should always be supporting him, and you should face the direction of the land as he'll most likely naturally want to swim back to land. Then lower him in so he is swimming but still have your hands underneath for support if he needs it. Walk into shore as he swims. Encourage him the entire way and be really excited for him. Really short swims are best to start with, start just far enough out that he can't touch. At first it should mostly be running in and out of the water and getting comfy with it, not you carrying him out to have him swim back to land until he is comfortable with you doing that. (I actually did carry Denali out and have her swim back several times as her water experience is mostly the beach, and she needed to know how to swim and to swim to land). Water is a WEIRD surface for most dogs to figure out because they step and their legs go down into the water before touching the ground again. It's confusing and scary at first for many dogs. Be patient, have fun, make it a game, and give lots of praise and treats.