Timeshare Booking 10 Months Out Share I want to book my timeshare the earliest day possible!If you can book 10 months before the day you start your vacation, then use this calculator. The First Day In Your Timeshare* (dd/mm/yyyy)The field below will show the estimated earliest date to book your timeshare. For example, if you wanted the week of December 20-27, 2023, then you would have to book by February 18, 2023. Your timeshare company should have the exact times for your booking.Estimated Earliest Date to Book Your Timeshare (dd/mm/yyyy)