A timeline for a destination wedding runs earlier than one for a wedding at home, for two reasons. Guests have flights to book and leave to request, so save-the-dates and invitations go out sooner. And a legal ceremony abroad adds a foreign registry's dates to your own.
This example counts back 18 months from the wedding day. The checklist below holds its eight anchor dates, and the sections after it take each stretch month by month.
Treat every date as a suggestion. The deadlines you have to meet are in your contracts: the venue's payment schedule, the hotel's room-release date, the caterer's final headcount. Put those in a calendar first and fit the suggested dates around them. With less than 18 months, or a venue already booked, start from the tasks still open; there is a version for 12 months or less further down.
To see the plan against your own date, enter it in the planning timeline tool, which returns dated milestones and a calendar file.