Ferry from Holyhead to Dublin

If you don't have a reserved seat, then you are free to wander around a variety of public areas, including bar, shopping, and other seating. In general on ferries, many people don't reserve. Boarding early will help you have a choice of other spots, if you're planning to park yourself. Both Stena Line and Irish Ferries have photo tours on their web sites.

We did the trip last September and were perfectly happy and comfortable on the regular seats. Whether you take the high speed or regular ferry, these are big ships and there is plenty of space and room to walk around and enjoy the trip. I have no idea what the bunk facilities are like but since the slow ferry only take four hours, who needs a bunk?

The reserved seats are well-cushioned, semi-recliners. They're yours for the duration even if you're not in them.

Anything else ranges from the type of bench found in a restaurant booth to airport-type chairs to tables and chairs in the cafeterias.

It varies by line, but if the reserved-type seats aren't claimed (not just unoccupied for a while, but actually not reserved), they're up for grabs as well.

If you've been using a non-reserved seat and get up to wander around, you've lost your dibs.

Bunks are only available for night crossings, I think.

The max crossing time is something like three and a half hours. You'll probably wander around for a couple and eat for close to another. I've never been on a ferry that didn't have way more than enough seats for everyone embarked.

Thanks for all the info. That's what I figured but I'm the one that's responsible for this section and want to get it right.