Your itinerary enables you to cross the International Date Line. This imaginary line across the Earth’s surface approximately follows the 180th meridian in the Pacific Ocean. Because of the roundness of the Earth and the necessity of having reference time meridians, we have to change dates when we cross this line. So if your ship is travelling west, you will need to add a day to the expected date; conversely, if travelling east, you will take away a day. This paradox, already noted by Magellan’s crews during his circumnavigation, serves as dramatic motivation in several novels, including Jules Verne’s famous Around the World in Eighty Days.