This question has been asked and answered many many times in great detail. To view earlier replies simply type petersburg into the keyword section of the 'Find a Question' box (highlighted in blue). In here you will find many responses and I think the one to portergill of Bristol with 20 replies, should answer your question (to which I think you will find the answer to be a resounding NO!).
No, No, No not on your own. Go with a local tour company or the ship's excursions. ... Neil.
Royal Caribbean - Independence of the Seas - 14 Oct 17 - 7nts
Southampton : Gijon : Bilbao : Cherbourg : Paris (Le Havre) : Southampton
Now from £579pp
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P&O Cruises - Ventura - 13 Nov 17 - 11nts
Southampton : Lisbon : Valencia : Cartagena : Gibraltar : Seville (Cadiz) : Southampton
Now from £599pp Was £639pp
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Princess Cruises - Caribbean Princess - 20 Apr 17 - 11nts
Southampton : Guernsey : Cork : Dublin : Hamburg : Rotterdam : Brussels : Paris : Southampton
Now from £999pp Was £1329pp
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