time difference in regard to excursions

Will be stopping in St Thomas and St Maartin next month on a cruise. I keep reading about keeping in mind the time difference when booking. Are both islands an hour later then EST? If the port time is 8A to 5P, is that not the same time that the island goes by? Will it actually be 9-6 there? Don't want to take a chance on booking something I can't actually do. Thanks for any input!

Both islands are on Atlantic Standard Time (UTC - 0400), which is one hour later than Eastern Standard Time (UTC - 0500). The port time will be on ship time - which can change to AST or can stay EST depending on the captain. So, no, the port time is not always the same as island time - port time will be the same as ship time.

Any ship excursions will be on ship/port time, but for non-ship excursions you will have to consider a possible time difference. So, if you arrive at 0800 and you have a local excursion booked at 0900, you will most likely be late since it will take you some time to get off the ship. However, the people that run the excursions are very aware of this, so if it is close, you should contact them and let them know what ship you are on and what time you arrive and they will make sure you don't get left behind.

Thank you so much for the information!

Can't speak for the other lines but Holland America Ship all move their clocks to the local time before you reach the port. However - weather or port activities my delay the ship from arriving at the scheduled times. All of the vendors in the islands know this and will normally wait if a ship is delayed.