Definitely a must do while in Montreal! There is a lot to see, eat, and do! Start off with some of the local cuisine (poutine!) in the food trucks. There is also usually a little arts festival along the port as well.
If you have young kids, there is a little train that takes you around, bounce houses, bikes, carts, and paddle boats! So much fun!!
There is also a zip line and high ropes course for the thrill seekers!
The only downside to the port is the abundance of aggressive seagulls and bees! I have a little 10 month old and I was constantly swatting them away!