More often than you'd expect though, holiday makers arrive late back from their time on land to find their boat already pulling out to sea.
The problem is how to get them safely aboard without significantly delaying the cruise and accruing significant costs.
Cruise Travel insurance policies will often cover 'disaster recovery' and 'missed departure', but you could find the extra costs of being tardy may come from your own pocket.
Sometimes, the boat will return to the dock if it has only moved a short way off, but this is at the discretion of the captain, the liner company and the harbour.
More often, if the liner is still within sight of stranded passengers on the pier, it may slow or stop and then send back a pilot boat or a launch to collect them.
The aim then is to get the latecomers alongside and up the side of the liner without waiting too long, and without spilling passengers into the sea.
In this situation, you want to avoid dipping into your cruise travel insurance to pay for injuries from a failed boarding attempt.
Don't Be Left Hanging In an unplanned boat-to-boat transfer of this kind you may be urged to jump from one boat to the other, or it may require a tentative ascent up a swinging rope ladder.
It should be noted that often the assisting pilot/tug/launch boat operator will charge a fee for the service, and indeed cruise operators may choose to penalize for the delay, which likely won't be covered by cruise insurance.
What it will certainly mean is the unwanted attentions of your fellow passengers.
In less favourable sea conditions they may cheer your successful arrival on board, but if you've caused a significant delay you may have to tolerate jeers such as 'buy a watch' or 'swim for it!' Worse still is when you miss the boat by such a margin that it is far out of reach.
When this happens your only recourse is to arrange your own transport to rejoin the cruise at the next port of call.
This could be costly, so it is a good idea to check if your cruise travel insurance covers you for such misadventures, and a better idea to be punctual.
Getting on Board But there are occasions when late boarders are not welcome on the boat at all.
A few days ago (in April 2009) the Italian Cruise liner MSC Melody had to repel repeated raiding attempts by armed Somali pirates who tried to climb aboard from a motor launch.
One passenger was central to this action as he threw his deckchair at the boarders.
In some reports he was hailed as a hero; other reports say the captain's order to go below deck went unheeded, exposing passengers to danger.
Although medical costs are covered by cruise insurance cover, a little sensible precaution might help prevent taking bullet wounds home as souvenirs.