Hello Ifite,
I guess your real question is what time should you arrive at the pier. Well there are lots of people who have no problem with waiting in line for a hours. They will show up at 9 am, and happily wait on the off chance that they will be the first aboard, and short of that, just get on early. Sometimes that pays off. Sometimes it just means a very, very long wait.
Tbrat is giving you the official times that boarding is supposed to begin. The actual time that boarding starts is always dependent on lots of factors. Like how early or late customs clears the ship, how quickly the previous passengers leave, and any number of other variables and possible delays.
It is not unusual at all, for boarding to start earlier. Eleven am is not at all strange. On the other hand, just as often it can be delayed till 2 pm or later. Occasionally, much later. Just ask all the 260 CruiseAddict's who had to wait till nearly 3 or 4 pm to board the Mariner for the MOSAIC group cruise. I don't remember the reason, but that time, boarding started then stopped for several hours.
For a better answer, why not ask other what time the other posters like to arrive at the pier, if boarding is supposed to start at one.
My answer would be "usually noon." But I'm dealing with a hubby that really hates lines. If I had my druthers, I'd show up at 11., or maybe earlier. As it is, I can only talk hubby into to heading over to the pier right after "check out time" at our pre-cruise hotel That is usually 11 am. So we check out, grab a taxi and head to the ship. That gets us there sometime between 11:30 and noon. Usually we end up waiting a little while, even then.