The Grand Final of the Eurovision Song Contest 2025 will take place in St. Jakobshalle, Basel, on Saturday 17 May with Semi-Finals on Tuesday 13 and Thursday 15 May, after it was selected by Host Broadcaster SRG SSR and the European Broadcasting Union (EBU) to host the 69th edition of the Contest.
As far as I’ve read there were four towns that applied for hosting the event. Montreux wasn’t among them. They might not have been interested. They have the Jazz Festival and I guess that takes a lot of capacity.