Depart UK by Air or Ship?
(Taken from the UK Immigration website)
You might be eligible for ‘transit without visa’ if: you arrive and depart by air have a confirmed onward flight that leaves on the day you arrive or before midnight on the day after you arrive and "have the correct documents for your destination (eg a visa for that country)
Two passengers, One a US passport holder and one from Thailand with a valid USA Visa, will be arriving from Bangkok by air but are departing Heathrow to the UK Southampton Pier on the same day for a direct transatlantic Cunard Cruise to the USA
Would this situation suffice for a Heathrow to Southampton Pier "Transit without a visa: and allow air travel to Heathrow without a UK visa?
Best Answer
There's not much to misunderstand in the text you quote, is there? Transit-witout-visa is only available if you arrive and depart by air, which you don't.
The American is visa-free for to the UK in any case, and so doesn't need a visa anyway.
The Thai will need to apply for a Visitor in Transit visa in advance.
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