The wooden bridges are open year-round.

Yes. The bridges themselves are built above the river and don’t get taken down for ice. The City of Calgary keeps the pathways on and around Three Sisters Islands plowed and salted in winter. Ice on the river doesn’t affect the bridges—you’re walking above it.

If you’re worried about slippery conditions, that’s a general Calgary sidewalk issue, not a bridge closure issue. Just wear boots with grip.

The islands are lovely in winter. Fewer people, frozen river views. Go for it.