Using public transport only is a bit sticky, but you can fly to Boston/Nantucket. Expensive but nice.

Myrtle Beach HAS changed--one of the fastest growing cities in the US. But as I said, Litchfield is a wonderful quiet beach but close to all the hurly burly you might want. BUT public transport isn't gonna be there.
Our kids that age were satisfied with the beach and miniature golf. There are plenty of sights near in MB--Aquarium, shopping, pirate ships, Brookgreen gardens (small zoo, butterfly pavilion), Huntington beach state park with nature walks and alligators!
Surfside Beach, Garden City also are just south of MB and north of Litchfield/Pawley's. MB airport is small and dead easy to get in and out of --AND rent a car right there.

Tidy, I have not been there but I will check with people I know who go there.

Mocha Dolce, Was just there in September. Beautiful area. We got reasonable flights into Logan, stayed a week on the cape and used the ferry to the islands.

Gretchen, Do you know where I could find the most current info on rentals? Accommodations are not always what they say they are.

Happy Trvlr and ten thumbs
Which area of San Diego would offer the most and be the safest for young children

If you are talking about Litchfield, then google Litchfield Beach and Golf Resort. You want to go for a week in high season on the SE coast. If you choose a town, then you'll have to google for the realtors in that place, in my experience. I'm not clear where you want to look now.

Sorry, I mistakenly thought Litchfield closer to Myrtle Beach. Need to google maps before I reply.

One thing to consider with children is that the Pacific Ocean is much colder than the Atlantic. And with the Atlantic the further south you are the warmer it is.

omg, I hate this new forum, just lost my whole post. Public transportation sucks here in Fl, maybe a resort would work for you. I grew up in Lewes and Rehoboth Beach. Book a condo or cottage last week though. Tybee Island, Amelia Island, St Augustine Beach. I live very near New Smyrna Beach. Great vibe, downtown beachside is wonderful, shops galore.

So I grew up going into the cold waters of the Pacific. I didn't mind it at all as a kid. Much colder somehow when I had my own little ones. I sure was glad my husband was willing to endure that cold water with them.

Also, I have read that some of the East Coast beaches are so calm that you can actually swim in the ocean. I would strongly discourage that with children for most places I've been on the West Coast. Too many dropoffs and sneaker waves. You can definitely wade and fetch water for sand castles.

It is 20 minutes south of Myrtle Beach and its gridlock traffic and craziness!!
You can stay at Litchfield, have an UNcrowded beach (and ocean front accomodations) for the fun Then if you want miniature golf, go 10 minutes up the road to Surfside and its water slide and miniature golf. OR go on to MB.
YOu can stay OUT of the traffic gridlock and see Brookgreen Gardens and Huntington Beach State Park, just across the highway from Litchfield.
It sounds like you want to stay in Myrtle Beach. If so, you'll just have to search. We have had our beach place at Litchfield for 20 years and have gone no further into MB than the airport or the bypass to get north of MB.

Yes, we actually do swim in the ocean in New Jersey particularly after the first of July when the water warms up. And doing so at low tide is really fun for the kids!

Also, I have read that some of the East Coast beaches are so calm that you can actually swim in the ocean.

OH, my goodness!! As I said, that is the attraction of the North and South Carolina coasts!! Not so great for surfing but the sand extends far out and makes the breakers just right for moms and dads to toss kids into the waves. OR it can literally look like a pond. Swimming in the ocean here is June to October at least!!

Not renting a car effectively eliminates the Outer Banks and most other beach towns in the Carolinas. You would be fine without a car in Rehobeth Beach which has a boardwalk and a lot of restaurants and activities (also true of Ocean City, MD,) but I'm not sure how convenient it would be to get there.

This is turning out to be more difficult than I imagined when I got this idea. Flights are two or more stops to just about every location I've inquired about. Bringing or obtaining car seats was a major determining factor in not wanting to rent a car.

Which airport are you flying from?

Car rental agencies will supply the car seats.
BUT you may want/need to bring car seats on a plane with you, which for 3 little ones (I think) may be really daunting. I also wonder if you are doing this as the lone adult. To me, overseeing 3 small children at a beach would be too dangerous for my taste.

Look at Disney's Vero Beach resort in Florida. They provide transportation to and from Orlando.

How many adults and what ages are the children? Renting/driving a van might be easier than public transportation if it's only you and one other adult with three young children. Sea Pines Resort on Hilton Head Island is 45 minutes from Savannah airport and provides a variety of activities for all ages: beach, children's museum, dolphin cruises, special children's concerts, a stable with pony rides, just to name a few. And you can rent condos/THs/homes with room to spread out. Look for a unit with the children's equipment you need or rent from one of the agencies that supply what you need. There is tranportation from the airport and a bus in season to get around, but I recommend driving from the airport because you will have many more options for groceries, family style restaurants, activities. Also easy day trips to Savannah, Charleston, plantations. Did this with our extended family including grandchildren recently.