Port of Southampton to London Centre?
 

We will be disembarking a cruise ship in Southampton and going to a hotel near Oxford Circus tube station.

What is the most convenient way? How much? When and where should we book?

you can take a train or the National Express bus and then a taxi - i don't know the current fares but you can do a search and find the info. My preference is to arrange shared van service with Silver Fleet from the dock to my hotel. Yes, it costs more (around 59 Brit. pounds per person depending on hotel location)but it is very convenient,reliable, and comfortable - certainly worth it to us. We have used them several times book and pay over the internet.

Check to see if anyone else has a van hired. Go to www.cruisecritic.com and look for your cruise line, ship and date of sailing and you can check the boards for anyone looking to share a ride.

We just did a transatlantic in Nov. and our ship left from Southampton and I booked National Express bus from London to Southampton station (did not take us directly to our ship), stopped at the bus station. We then took a taxi for the very short ride to the ship. It was simple, easy and a nice ride. You can check out: http://www.nationalexpress.com/home.aspx

I just did a check of bus services on National Express and it does offer bus services directly into London Victoria Coach Station, you would then have to take the tube or taxi to your hotel. I didn't have your date but just plugged in May 1st and they were offering "fun fares" for 13 pounds for two. This is the rate we paid and it is a fantastic deal. Again, didn't know if you are "seniors" etc. so you can check it yourself. I booked online, got my printout and gave to bus driver. I would suggest that you book ASAP because those fun fares go quickly. It was a pleasant ride into London. You might check your hotel and see what they offer for taxi fares to pick you up. London taxis are not cheap but we did use them quite a few times. With the fun fare and a taxi, you still would get a fairly inexpensive ride to London and hotel. You can easily walk out of the bus station and find black taxis everywhere, ask what the rate will be to your hotel. Typically it will be 10-15 pounds and w/ your fun fare is not a bad way to go. Also remember you won't be able to check into your hotel until 2 pm (check in times vary). Most hotels have a luggage storage area and you can drop your luggage off and go sightseeing. This is what we did. Have a great cruise and London visit.

One other thing I forgot to mention, if you book National Express online make sure that you have notified your credit card company that you are traveling and the dates or National Express will decline your card. Happened to me, duh I forgot to notify my cc company.