Many thanks again. I think the Kiahuna would be fine even without the pool because I want to enjoy the ocean. Thanks for all the help.Lin

The beach in front of Kiahuna can keep your children busy for days. The left side (towards the Marriott construction) will be perfect for your 6-year-old. It's quite calm right there. Our 7-year-old discovered snorkling while swimming there and we couldn't keep her out of the water. There is also a path that runs in front of the Marriott property and takes you to Poipu Beach Park. There are nice tide pools to explore out at the end of the point there. Also, my kids love theshave ice at the snack shop at Brenneke's, across from the beach park.
My kids (both girls) also like a trip to Spouting Horn. We always give them so money to buy trinkets and souvenirs from the stands there. Waimea Canyon is beautiful. We've had trouble with one of our kids getting carsick on the ride up and if there has been rain the trails can be very slippery. My kids still talk about a funny waterfall hike we took that was in the 2nd edition of the Ultimate Kauai guidebook. (It's not in the 3rd edition.) The map was a little iffy and we got lost and never found the waterfall but really enjoyed an easy hike down to the river in a beautiful setting. We felt as though we were a million miles away from civilization even though we were probably only a couple of miles in from the Coconut Coast. As we walked into a forest glade on this little hike, we saw bits of pink color on everything. Realized someone played paintball down here. In the middle of the pink glade was an abandoned toilet. This cracked my kids up and they still ask to go on the "toilet hike."
We have also taken our kids kayaking. Your older two could probably handle their own dbl kayak or you could put one adult on each boat. We have put on younger child in the middle of the kayak and she has done fun. The big dbls are virtually impossible to tip over and everyone is given a life jacket and a cooler for each kayak. The trip up the Wailua river is really fun.
We have also visited the Kilauea Lighthouse. (Call ahead for a tour.) The birds here are fantastic. We generally make this stop on the way up to the Northshore. We drive all the way to the end of the road to Ke'e Beach (beautiful view of Bali Hai and good snorkling. Also lots of Kauai jungle fowl (wild chickens.) Hanalei Bay is also a great spot to play. It's a bathtub in the summer. Great shave ice at a little trailer in Hanalei Village.
(Try it with ice cream, very tasty even for a grown-up.)
Kalapaki Bay, in front the the Marriott in Lihue is also a fun beach with kids. There are bathrooms and showers there, also a good little hamburger spot across the road- the Beach Hut- with outdoor tables and great fries.
Also, Maha'ulepu Beach, down past the Hyatt in Poipu is fun. It's access is down a bumpy cane road. We like the beach that is past the first parking lot and is visible from the road. There are great beach walks along the dunes and a rope swing on the beach. Really beautiful and a little remote.
Also, your kids might enjoy "Parrot Talk," a free daily program at the Hyatt (10 am each day.) The kids and adults get to hold the hotel's macaws and learn about them. Very informal and fun. Also, for a splurge, there is a day rate available at the Hyatt. You can rent a room from 9 am to 6 pm for half the price of the lowest roomrate, not a bargain but really fun on a nice day to use their incredible pools.
Also, a visit to Walmart near the airport is a great place to pick up beach toys and puzzles (good for a rainy day - we are convinced that buying one actually keeps the rain away.) Also, Border's books at Kukui Grove has great books, a huge Hawaii section and a great music selection.
We love Kauai and am sure that your family will have a ball.

MJ, thanks for such great ideas for our family vacation in Kauai this year.

As a general question for all of Fodorites: does it make sense to buy and bring our own snorkeling equipment? Or should we rent or buy in Kauai? Any recommended places to rent/buy?

Iza,

It is not worth bringing all of that gear. Too bulky. You can rent gear so many places. Many of the places are right on the beach, but there are some shops that rent much better equipment.

Have fun!

I am surprised that no one has mentioned Lydgate Park on the east shore just a few miles from the airport on the way to Kapaa. It is a family oriented site with a large natural ocean swimming area enclosed by a man made reef wall of rocks. There are no large waves in the area and snorkling is pretty good. Lots of large fish and colorful fish to see. Also the area has a huge childrens play area with slides, climbing apparatus etc.. There are picnic areas and places to have a family bbq or picnic. A nice place to spend the day and let the kids swim and snorkle without fearing the large waves. Check it out.

lin & lza Lyngate is a great place to introduce snorkeling to the young ones. Kauai ultimate guide recommends this. We ignored this last year thinking how hard is it too snorkel took the kids to tunnels first, one kid was freaked out by how close the rocks were while he snorkeled would not have been a problem had we gone to an easier spot first. Instead I was chasing a traumatized kid down the beach with my own jet lag.