Are you sure about staying at a Heathrow hotel?

That will not be at all convenient if you intend to go into London every day.

Southwest trains have a frequent service from Waterloo station in London to Southampton.

If you have to go from Heathrow to Southampton,get a cab to Woking station and pick up the train there.

Go to the Southampton forum and look in there this question comes up frequently and will have been asked and answered dozens of times.

BTW, staying near Heathrow airport to sightsee London is generally not a good idea for many reasons. I suggest you look into staying in central London to save an hour to 2 hours commute each way each day, plus have something to do in the evenings because there isnt much around the Heathrow hotels..

There are plenty of trains between London Waterloo and Souhampton - for time tables etc see www.nationalrail.co.uk

If you do stay at Heathrow, there is a regular railair coach link to Woking Station from Heathrow Central bs station. Through tickets are aailable

You will probably need a taxi between Southampton Central Station and the Terminal.

"there is a regular railair coach link to Woking Station from Heathrow Central bs station. "

Or just get the direct coach to Southampton from the same bus terminal. Doesn't alter the fact that Heathrow is a very poor choice of location for sightseeing London.

There are 3 trains an hour from Waterloo to Southampton, so I have no idea why you can't find them (especially whe ngoogling London southampton train gives you the direct rail site as the top hit). It takes 1hr20 mins. There is no reduction for booking in advance so you don't need to. Avoid rush hour (5-7pm) or you will end up standing to Winchester (1hr). Other than that it doesn't tend to be very busy.

The station you get off at is Southampton Central (Southampton Airport Parkway station is, you've guessed it, at the airport and not the city centre). You can walk to the cruise ship terminals from there, apart from QE2 terminal which is a bit further away. But I would recommend a taxi because you don't really want to wander around an industrial dockyard carrying all your luggage. There are a zillion taxis (all white if S'oton city council registered) outside the station.

If you are travelling from Heathrow, the easiest way is by National Express bus from the bus station at terminal 1. Thus takes about 1hrd 40 mins and goes direct to the city centre. When you get off in Southampton, go round the other side of Toys R Us and you will see the station and taxi rank right there (they are obscured from view by the big shop).

Put in Southampton Cruise Transfer into Google and loads on taxi services comes up which can take you direct from Heathrow Airport Hotel to Southampton Cruise Terminal.

I would like to thank all who took the time to help me.You are very kind to do that. You have been so much help,now know of many options where before I had none. Thank you so much, wheres