Lydgate is a sure bet. There were other families here but the beach was large enough that it never felt crowded.
Poipu Beaches: We first went to Shipwreck beach in front of the Hyatt. It was a pretty beach…to look at…but not to swim! I guess if I was staying at the Hyatt & had use of their beautiful pool area, that would be ok…but we wanted to be able to get in the water so we packed up & headed to Brennecke’s by the Marriott. There were more people on this beach than any other beach we visited in all of Kauai. If serenity, solitude, and quiet strolls on the beach are your thing, this is not the place! Our family had a fun time here..lots of other people around to mingle with & the boogie boarding & snorkeling was fun.