Last time I visited Toronto Islands, it had been a while since my last summer visit. I was impressed!!!
There were more people than when my kids were young, but everything was really well organized to maximize everyone's experience to the Islands.
I was with two teens (I will later post tips to better enjoy the place with teens) but had a good look at what would appeal to me, were I to return with younger kids.
My TIPS for a great visit WITH YOUNG KIDS:
1) Prior to your visit, go online to buy Centreville Amusement Park tickets (you save money and will avoid the crowd at the gate. It is absolutely perfect for kids 8 years and under.
2) Check the Centre Island ferry schedule and arrive at the ferry docks (at the foot of Bay Street) 45 minutes prior to departure, with snacks and water (and maybe chalks so the kids can draw on the asphalt while you wait). DON'T FORGET TO NOTE THE SCHEDULE FOR YOUR RIDE BACK!
3) Bring cash to pay for the ferry ride! (Last time I checked, it was cash only.)
4) Once on the other side, go directly to the amusement park, a short walk off the Centre Island dock.
5) When the kids are ready to cool down, go to the great spray pad outside of the amusement park. To reach it, cross the big bridge to your left as you exit of the amusement park. Walk until you reach the fountains on each side of the alley, and go to your right. The spray pad is hidden from the sight because of the trees but it's there! And it is very pretty.
Of the ferry, you'll see signs (and probably some of their wacky characters) for the Lagoon Theatre 30-minute pay-what-you-can performances. I'd save this attraction for kids 7 and older, simply because the amusement park and the spray pad is already a full plate for younger kids but the show is suitable for 3 to 12 years old.
On the way to the amusement park, you might also catch one of the 10 Minute Drum Circle (when we visited, they offered free playshops and they supply the drums, not sure it's still going on).
Also read 5 TIPS: Toronto Islands with older kids
Also read 8 TIPS: Toronto Islands with teenagers