Boston Must Do's with 4 year old
 

Good evening! I am going with my husband and my 4 year old little boy to Boston. What are some of the must do's?

There’s a children’s museum that looked fun.

What time of year is this trip? Outdoor skating if it’s this winter.

Read Robert McCloskey's " Make Way for Ducklings" together, then visit the sculptures of the ducklings in the Public Garden.

In warm weather, take a swan boat ride in the Public Garden. In cold weather, skate at the Frog Pond in the Common, go to the Children's Museum (as above) and go to the Aquarium.

Don't know where you are staying, but the Marriott Long Wharf has a pool overlooking the harbor, is adjacent to Columbus Park for running around, and only a few blocks away from the pastries of the North End. I am not a Marriott fan, but this one works well for little people.

Yes to Ackislander's suggestions.
If it's running I'd also take the DUCK tour as little ones often get to help 'drive' the vehicle when its in the Charles. Ask about this when you board ( or call in advance).

The Science museum might be worth it depending on your son's interests or possibly the Public Library. It's a beautiful building and there are frequent story telling times in the children' room or perhaps it's a good place to sit and rest with a book during the day.

My daughter is that age and LOVES the Aquarium. Definitely her favorite spot in Boston, plus it is a great area to walk around and explore. My tip is to get there early. Especially on weekends and holidays it can get VERY crowded. Even on these days though, if you go when they open it will be pretty empty and much easier to explore for 2-3 hours before it gets real crowded.

She also enjoyed the Museum of Science. Not everything in there was interesting to her but enough to make it fun. They have a 4-D theater that plays kid friendly shows that she loved, too. The one we saw was a little episode of Thomas the Train.

The Children's Museum is great, too, but we usually avoid it because of the crowds so I have only been twice.