Loxocele R.
Yelp
Singing Beach is lovely, but probably not worth the trip for non-residents unless you can go at weird/off-peak times.
As of July 2016, the sign at the lot right next to the beach says "RESIDENTS ONLY" for the duration of the season (which ends 30 September). There are free 2-hour spots along Beach St, but moving your car every 2 hours is a drag when it takes 20-30 min to walk (round trip) from beach to car. The real trick is Masconomo Park half a mile away: while *most* of the spots there are resident only, there are a few that aren't. Come on a random 90-degree Tuesday, read the signs carefully, and you might be one of the lucky ones. Walk-on fee is $5 for the over-12 crowd.
Once you get to Singing Beach, it's great. The sand is somewhere between "tropics" & "playground"; the dry stuff will scorch you good, but it's still soft & the wet sand feels great to walk on. The beach is clean (no trash), and--likely because of the parking situation--not crowded, at least on a weekday afternoon.
The water, otoh, is COLD COLD OH GOD COLD--cold like eventually your feet will ache; cold like if the air temp weren't 90-whatever degrees, it'd be hard to go in past your knees. (The sign at the entrance said water temp today is 64, which *sounded* warm when I read it; shows what I know.) That said, the bottom is soft, the water is clear, & there's minimal sea debris. I spotted a few creatures in the water, too: little centipede-looking waterbugs, schools of tiny shrimp-shaped critters, and one orange crab the size of my hand. Awwwwww.
Other notable wildlife includes the seagulls, which are ballsy as fuck & too smart for their own good. If everyone in your party goes to the water at once, the gulls will come and they will go through your stuff and when they find a bag of chips in your bag, they will *recognize it as a bag of chips* and abscond with it to go rip through the packaging. If you bring food (even unopened food), bring it in a zippered bag or latched cooler unless you're intentionally catering for your web-footed friends. (There were a few flies that appeared by mid-afternoon, but they were easily dissuaded even by herbal DEET-free bugspray.)
All in all, a great place to spend a day swimming & reading *if* you're up for driving all the way to Manchester w/only slim chances of finding a parking spot.