Ireland Things to do on a Cairnryan to Larne Crossing by P&O Ferries June 7 2019June 29 2023 Our speedy North Sea crossing will get you to Northern Ireland in just two hours, and there are some great things to do on a Cairnryan to Larne crossing that will make it feel like you are on board for barely any time at all! Share this:FacebookWhatsAppMorePinterestLinkedInPrintTelegramTumblrRedditPocketTwitter