London transportation to Southampton

Hotel to Waterloo Station, by Underground or cab. Use the journey planner here: http://www.tfl.gov.uk/ Waterloo to Southampton Central station, at least 3 trains per hour, journey time around 1 hour 20 minutes. It's a South West Trains service, so check times and buy tickets on http://www.southwesttrains.co.uk/ . I commute on this line and would not recommend any late afternoon departures after the 16.35 on a weekday, if you want to sit together and be able to keep your luggage near you. I expect you will travel earlier in the day anyway. Southampton Central to your ship - get a taxi right outside the railway station. Different cruise companies are based at different dock gates, so there isn't a single "cruise port" as such. They should tell you which dock gate you need, but I'd bet the taxi driver will know which ship is where. Cunard has a handy map which shows you where the various cruise terminals are, as well as Southampton Central station: https://ask.cunard.com/resources/carnivaluk/before-you-sail/southampton_map