There are regular ferry services to the island from Burtonport starting early in the morning and running almost hourly throughout the day. Timetables can be found at the harbour in Burtonport, or you can contact the ferry operators directly for more information.
There are regular bus services running from Burtonport to Letterkenny.
Letterkenny to Burtonport (271) can be found on Local Link Donegal
Dohertys Coaches also run a service, timetables can be found on their website