Tickets purchased are valid for any sailing on any day within their Validity period (12 months for all tickets with the exception of multi-trip tickets, valid for 18 months from date of purchase) You do Not need to pre-book a sailing time. Arrive to the terminal 15 minutes prior to departure times. (Sailing on the Hour every hour from Greencastle terminal 10.00 - 17.00 / Sailing On the half hour every hour from Greenore 10.30 - 17.30)