The beach directly in front of Tuy Hoa town is okay, but it has a problem.
There is a massive sandbar extending about half a kilometre out into the sea. At high tide the water is about waste deep, and at low tide it might only be up to your ankles. The only way to go deeper is to slog through 500 metres of water, which is not recommended and there are buoys to discourage you from doing it. The sand bar is visible, and actually quite beautiful, from the viewpoint on Chop Chai Mountain. You can also see that it's shaped like a large semi-circle, so that the beach further to the north and south doesn't suffer from the same problem. If you're a beach-lover, plan to use Tuy Hoa as a base for exploring the beautiful beaches further afield.
If you head north on Doc Lap Rd, past the seafood places, the road eventually turns to gravel and extends for another seven kilometres before turning into sand -- un-navigable unless you go it on foot or you brought a dune buggy. Along the way are countless options for taking a dip in waters that are much nicer than the ones in town. About 4 kilometres along the road there's a second collection of seafood places so you can eat, drink and be merry while you enjoy the sand and sea.