Check out the mini golf at Pastory Gardens for the kids.

And now your countdown begins!!! Palm Terrace is very nice and close to town. There are a few steep hills to climb, tho. but better than having to drive to town!!! ( parking is an issue) and it is so nice to walk off that dinner! will you have a stroller for the little ones? You will def get a workout! which units are you staying in? You may want to bring some ear plugs...the roosters start crowing at 3 a.m. Other than the pool and beach, there is not much else...we are all in bed by 9 or 10 because of being active all day!!!

Dont know if you are bringing strollers but the Westin Hotel grounds are open to the public. The parking area is to the right of the main lobby as you drive in and there is a lot of level ground to cover all around the pool and along the paths that travel between the beachfront and poolfront buildings. There is an iguana feeding on the grounds--not sure of the time, but maybe the 3 yr old would at leat enjoy seeing an iguana. The paths are pretty level and it is one of the few area on St John that I could even think of taking a toddler by the hand and walking around.
The pool restaurant and bar is open to the pubic and you could grab a beer and something light to eat for the kids during happy hour, with plenty of room to park the strollers. That area usually closes at dusk, but its a great place to sit and watch the sunset even after the bar closes. Also, the lounge outside the open air restaurant has some nice tables that will accommodate strollers. They are open much later, and the area is child friendly. Very near the parking area there is a small group of shops, as well as a deli, where there is also an area where you could let the toddlers out to stretch their legs.
Visited the Westin quite a few yrs ago with my 18 month old nephews, and found that it was a great place to stroll around with kids in their strollers. Each year when we visit the island with them, we try to get them down there to let off some steam after they nap as Its a pretty kid friendly place, and the layout of many of the condos /villas on St John tend to restrict their ability to run and play. Downtown Cruz Bay is not exactly stroller friendly as there are few area with level sidewalks.
As many of the restaurants, although child friendly, have limited space inside, if you have several small children with you and you want to get out for a casual yet comfortable dinner, you can also try the Beachside Bar/Restaurant at Caneel Bay. Beautiful grounds also, magnificent sunsets , better food than the Westin, although still a pretty casual meal. ( Crab cakes, salads, burgers, sandwiches ect) Caneel is very child friendly in that area in the summertime, and you will have lots of shade that looks out at the beach and the sunset. On Monday night, that area is closed for the managers party and the Island Buffet.at the adjoining Beach Terrace restaurant.
Hope this helps.
We have traveled to St John with our neices, nephews and gradkids for many years and have used these two places a lot.

I would recommend Westin, too. They have a nice play ground, iguana feeding, and cool parrots.

We are leaving in couple of weeks with our 2 year old toddler. I am packing a lot of off!, a few simple sand toys, SPF cloth. I am also trying to find a good floaty or swimsuit for my kid.

There is not much else to do with little one, other than beach and pool on STJ. I am also packing a few of his favorite DVDs.

Great info. Thanks everyone. We might have to try the Westin. Here's another question.

How long does it take to get from the airport to Red Hook for the ferry? Just trying to think of dinner time for the kids(and myself). That and letting the villa rep know when we'll get to St John.
If the flight arrives at 6:10 pm, do you think we can make the 8PM ferry?
There will be 6 adults + the 3 little ones in a taxi. I'm asking our villa rep to reserve the taxi for us. We aren't picking up the rental until the day after we get there because I'm thinking it would be too late and probably just easier to be driven to the villa by taxi.

no problem makeing the 8 oclock ferry you might make the 7 but doughtful