This is one of the harbor Pilot boats. They had dropped off pilots to command the 2 cruise ships that were scheduled to leave in a few hours.
Pilots will command the ships until safely out of the port. Then the ship's Captain will take over.

Most large cargo, passenger and even military vessels, use pilots when in foreign waters. In many cases, it is required by the government.
Although the Captain remains in command, he follows the pilot's advice in matters of coastal navigation and harbour maneuevering.
The pilot is a fully qualified master mariner who knows the area in which he works intimately, having spent many years captaining vessels before becoming a pilot.