Probably photographic identity such as a passport or suitable driving licence. Requirements depend on the ferry company.
That would depend on where you are travelling from and your nationality. If you are arriving from mainland Europe you will need a Passport to enter. Anyone leaving the Country and returning needs a Passport.
No
No.
yes you do in order to travel you must have a passport
For a ferrytrip from England to Amsterdam, the Netherlands, a passport is needed. During the trip, the border between the two countries is going to be crossed.
No but you will need photographic identity. Check wit the ferry company.
Strictly speaking, you won't need any ID to get on the ferry from Portsmouth to Guernsey. However, if you are not a British citizen, it might be best to take your passport with you.
no - it's an internal UK ferry trip
No but you do need I.D.
it depends how you are going to travel because it would take longer by ferry than plane..
No. You would have to travel to England first and get a ferry from there.