Water babies at the columbus centre
We've primarily used the rec centres for free swim. We really like Ethennonnhawahstihnen' Community Recreation Centre and Library (https://maps.app.goo.gl/YvnidD744vrFWsJn8?g_st=ac) but Douglas Snow Aquatic centre (https://maps.app.goo.gl/cGAfJiBuTN3YLE1D9?g_st=ac) is another great option! I would not recommend the swim classes through the rec program under 2 though. They don't really know how to teach kiddos that young (at least in my experience with my 10mo)
https://www.familyfuncanada.com/toronto/indoor-pools/ ^ rec centers by area in TO
Check WaterBabies. My son has swam with them since he was 3 months old. They use pools all over the GTA