It is provided your dog is not drinking the water or ingesting it as it retrieves toys from the ocean or pool.
My sister took her Lab to a friend’s salt water pool and he kept retrieving a ball. Suddenly his back legs went out from under him and he could not see.
He had been swallowing water while carrying the ball in his mouth.
If this happens to your dog you need to get them to the vet immediately as the salt needs to be flushed from the body as soon as possible. Just coaxing your dog to drink lots of fresh water is not enough in my opinion. The vet will most likely administer IV and/or sub-Q fluids to flush the body.
The dog may also vomit up the salt water but I would not consider that to be enough. Get to the vet.
From info I have read it can effect the organs and blood and the dog can die if not cared for properly and immediately.