This gets confusing fast and I think there are no standards in reality. I wrote a super long post and then dumped it.
There are lots of reasons for one or the other.
3 main considerations for me -
First - Most ports
only allow crew ashore to do immigration. Everyone else is supposed to stay on-board.
Second - Some ports
have landing fees
. If you have "passengers" they could presume you are a commercial operation and charge you some exorbitant passenger landing fee.
Third - The Captain
is usually responsible for the crew's conduct and to ensure their onward journey including paying airfare etc. If a crewperson gets sick and in hospital the Captain
may be responsible for all that and cannot leave until assurances are given and accepted. Some argue that this applies for passengers as well but I disagree.
In summary -
- Crew - Captain may be responsible for their onward journey and/or their conduct in port
- Passengers - May make you a commercial operation
Each country may have different rules and may not even apply their own rules consistently. My experience is they cut us non-profs some slack.
Professional captains & commercial operations not so much.