The beach is 2 miles long. There are also trails along the coastline and marshes, as well as miles of paved park roads (shared by vehicles, as well as foot and bicycle traffic).
Some notes from my family's experience:
Perhaps a beach outing is not top of your mind in winter, but the beach can be a great spot when trails are too icy and slippery to navigate! Hammonasset Beach has lots of options for outdoor play and exploration in the winter.
Back in November, we timed a beach visit so that we'd be ending our walk near sunset. The beach faces West, so it is wonderful for sunset walks.
This past weekend, we went mid-afternoon and parked at Meig's Point. Hammonasset is huge, with multiple parking lots. Once you are on the main park road, just keep heading left and following the signs for Meig's Point. There is a parking lot at the Nature Center, and another small parking lot even further down, past the Nature Center. We parked in the very furthest lot and then followed the trail all the way as far left as we could go. There are endless places to climb boulders and search for beach treasures. Not far past the furthest parking lot, you'll find two labyrinths made of beach stones, too!
A trail map is HERE. If you plan to stick to the trails then it probably does not matter if you go at high or low tide. If you want to walk on the beach or have lots of rocky areas available for playing on, you may want to plan your visit for low tide. A tide table is HERE.
If you are really lucky this winter, you might see a HARBOR SEAL! Harbor Seals visit the CT shoreline from about December - March, and are regularly seen sunning themselves on the rocks off of Hammonasset Point (going on a sunny day at low tide may be an especially good time for a sighting).
One more tip: check the hourly wind speed for Madison, CT in your weather app of choice. It is often much windier at the beach, and anything above about 15 mph can make a shoreline outing less fun. Your children's tolerance my vary!
