My Girlfriend and I were traveling from St John, Virgin Islands on a ferry-boat going back towards Saint Thomas approximately between 9 pm and 9:30 pm. So it had just gotten dark however a somewhat faint sunset light horizon had made the top outline of the Saint Thomas mountains visible. Way way above the the highest peak of the island mountains from our vantage point was an oval shaped object that appeared fixated in the same location the entire 20 minute boat trip back to Saint Thomas Island. The craft had multi-colored lights flashing around the center of the craft. This craft was so high above the island and it did not move at all for the entire 20 minutes that we had sight of it. Eventually we lost sight as we came upon the shore of the island of Saint Thomas. I personally concluded that this object could not have been a radio tower because it was way too high in the sky and that there was no structure directly below it. It certainly was not a helicopter, plane or a balloon because it did not move the entire time that I watched it for those 20 minutes. My girlfriend and I both agree that it was a UFO with flashing multi-colored strobe lights. We have never reported this before however we have always remembered our experience. We recently watched a series of UFO documentaries on the History Channel and thought that we show look for a website to record our sighting. Hopefully we did not wait too long for this to be taken seriously.