- The beach! Poipu, Anini, Salt Pond and Hanalei Bay are all great for kids. Don't forget shovels and pails or other sand toys.
- Kamalani Playground at Lydgate - it's huge and will easily entertain for hours - pack a picnic lunch.
- Koi feeding and Parrot Talk at the Grand Hyatt
- Spouting Horn
- Keiki hula at the Grand Hyatt and Coconut Marketplace
- Farmers Markets (well, only free if you don't buy anything!)
Rent bikes, Trail-a-Bikes and bike trailers from Coconut Coasters in Kapa'a and ride along the bike path. Don't forget to put sunscreen on your legs where your shorts will ride up while you're pedaling.
There's a new mini-golf place with beautiful botanic gardens on the North Shore and a 5-mile walking/hiking/biking trail.
The sugar cane train at Kilohana Plantation is fun for littles, especially because you stop halfway through to feed the goats and pigs. The train ride ends right outside Koloa Rum Co. for a little adult entertainment...
Na Aina Kai tropical botanic garden on the North Shore has a children's area and a special tour.
For music lovers, the McMasters host slack-key guitar concerts in Hanalei and Kapa'a.
The Kileauea lighthouse and bird sanctuary is a great natural resource and a good place to spot whales in season.
Check out Kamokila Village in Wailua for a view of Hawaiian culture and history, and outrigger canoe tours up the Wailua River.
Good Hikes with Kids
We have hiked the Kuilau Ridge Trail in Kapa'a a number of times now - it is a gentle slope with beautiful inland views and a lovely wide-open picnic spot about a mile in.
The Maha'ulepu Heritage Trail is a great tour of some rugged Poipu coastline (but go early or late, there's no shade).
Waimea Canyon hike suggestions from TA member KauaiHiker
The Cliff-Canyon trail isn't much harder than Kuilau, and it has great views of the Canyon you don't see from the lookouts. It has some sections where the kid can get out and walk, but it also has sections near cliffs and slippery edges, so keep kids close.
The Berry Flats Trail is very easy, has no dangerous drop offs. It's all in the forest with no views but there are mini-shelters built out of branches that children can play in.
The Iliau Nature Loop is a 1/3 mile easy loop with native plants (the iliau is endemic, found only on Kaua'i and mostly in this spot). It has nice views, in particular of the Wai'alae waterfall on the distant rim, and is worth a stop.
The other trail I always recommend is the Pihea Trail, at the last lookout along the rim of the Kalalau valley. You can go almost a mile of wide easy trail with nice views before it gets difficult, and then you just turn around.
Mommypoints in Kauai
A great travel blogger posted a review of some of the activities she and her young daughter did on their 2013 and 2014 trips to the island (including a helicopter tour!).