Holyhead Maritime Museum gives the port town a useful dose of local identity beyond ferries and onward travel. Its collections cover lifeboats, shipwrecks, naval activity, and the long history of Irish Sea crossings that made Holyhead matter.
The museum is small, but that suits the subject: models, photographs, rescue stories, and harbour material make a good stop before or after a walk along the waterfront. It is especially worthwhile if you are using Holyhead as more than a transit point.