P&O are not the only line cancelling Baltic cruises as Saga have too, but in both cases it is only around half the cruises that have been cancelled so I am sure it down to over capacity. If it wasn't safe they would have cancelled all Baltic cruises. I sailed there last August, choosing the itinerary because it never did have St Petersburg on it. Have been there, I wanted to explore other ports and there are so many other wonderful ports in the Baltic to visit - Visby, Bornholm, Copenhagen, Skagen, Saaremaa, Tallinn, Riga, Helsinki, Kemi, Gothenborg, Stockholm, Gdansk and, I am sure, more. It is a beautiful part of the world.