Roger W Wheeler State Beach

"Nice beach, low waves, good playground"

We went to this beach on a single day off in Rhode Island last year, and had such a good experience that we came back again a year later.  It's a bit expensive, we thought, to get in ($20 for out-of-staters, though I think that's the standard fee for RI state beaches), but the parking is really close, the sand is soft, the waves are low (there's a barrier or break or whatever you call it way out in the water, which calms things), the showers and bathrooms are clean, and there's even a playground if you need a little bit of a break from the water.  It's definitely a family beach, so your noisy and boisterous kids will feel right at home.