The only way you can leave the ship on your own is to organise a visa before you leave for your cruise. I think it takes 4-6 weeks to if you dont want to do that then it is either the ship's shore excusrsion or organise another organised tour with another company such as Red Octobe.
You will be well advised not to do anything other than use the ship's excursions in St. Petersburg. The tours arranges make sure that you will see the best that there is to see and get you into places better than you can do on your own. You must have a visa and they are very expensive if purchased beforehand and you can have a great deal of bother leaving the port and returning. Your security and safety is the other factor that you must face and there are a lot of ruthless people in that area. Should you become stranded and miss the ship your problems are magnified by 10. Quite honestly, for this port, I would recommend the ship's tours without any doubt. Neil Dow.
You will not be allowed off the ship if you do not have a Russian Visa. You will have to do the organised tours from the ship. There are several Russian tour companies who will provide the necessary docs to help you get your visa if you want - try Red October.
Look up a site called 'ship happens' - loads of info. We did St Petersburgh in May on a Baltic Cruise - teamed up with another couple and did a 'Red October 'trip. Basically cost the same as an excursion, but just 4 of us jumped all the queues without waiting for 40 people to catch up. Best way to do it. But don't bother with the second day - just do one day and relax the next. P and o tried to charge us £65 each just for the visa and the day didnt cost that for both.
We went on a Baltic Cruise with Celebrity on the Constellation in May 07 and it was brilliant ,we went on an organised trip to the Summer palace etc organised by the ship then stayed on board the second day and chilled out great Regards Iren.
Recently got back from a Baltic Cruise with NCL and organised our own tours (two day) with Alla Tours. Contact Alla the owner via email@example.com mention Bob Bowker and you will find her extremely helpful. They sort your visas etc., meet you outside customs, and show you more than you will see on a ship tour. Our guide was Angeleka and she was lovely. Spoke perfect English and was a fountain of knowledge. An added surprise bonus, we were presented with a 3 hour DVD as a memento. There are a choice of tours and you can go with as many or as few people as you want. Obviously the more the cheaper. As we only made the booking at the last minute it was too late to share, but believe me, it was a terrific and personalised experience to go with just a driver and guide in a really nice car (Audi) and worth every penny.