Connolly Station to Irish Ferries terminal transfer time

It is, it should only take 10 to 15 minutes and the shuttle bus to the port leaves Georges quay at 1250- which proves that there is time. BUT it is leaving nothing at all to chance- for the train being even slightly late for instance.
It also doesn't cover the eventuality of IF deciding to run the ferry early to beat incoming heavy weather.
You don't say where you are heading for when you get off the ferry- North Wales (or elsewhere in Wales) or the train to England.

Given that the conventional ferry at 1430 (the Epsilon) is not available that weekend I would travel on the 1445 Stena line conventional ferry Stena Estrid.

As you are coming from Belfast, if heading to England, I would take the ferry to either Liverpool or Cairnryan, or fly from either Belfast airport.

Thanks for the response. Sorry I didn't include the full details.

We are staying in Caernarfon on Saturday night, so the plan is to take the train to Bangor, then take the bus on to Caernarfon. The Estrid is clearly better from a connection standpoint, but if we take it, it appears we wouldn't arrive in Caernarfon until 21:15. I was hoping to avoid arriving so late.

If we miss the Swift due to our being late or the Swift being canceled, what is the likelihood of the Estrid being sold out. Obviously I don't want to eat the cost of Swift tickets, but I'd like to be prepared for the worst.

Another alternative would be to plan to stay in Dublin on Saturday night, then catch one of the ferries in the morning. Unfortunately this would require adjusting reservations that we have made for hotels in Caernarfon and Porthmadog. We could do that, assuming that is really the better approach, and that rooms are available.

Very unlikely the Estrid would sell out. She is a huge ship, and is a rail connected sailing so has to be able to take unbooked pax.

I love the Estrid, Edda and the Embla- very Scandi cool ships.

Better option- take the Coach down- more frequent and cheaper than the train- just £9.50

Take the 0900 bus, arrives Dublin Busaras 1145, stroll across the bridge to Georges Quay and catch the IF shuttle bus at 1250

Details and bookings here- https://www.translink.co.uk/JourneyPlanner?OriginId=suburbID%3A31400030%3A147%3ABelfast%3A733748%3A125917%3AITMR&OriginName=Belfast&OriginType=suburb&DestinationId=suburbID%3A57102020%3A10822098%3ADublin%20City%3A716464%3A265191%3AITMR&DestinationName=Dublin%20City&DestinationType=suburb&DepartureOrArrivalDate=2023-05-06%2004:55&isSearchByDepartureDate=true&FindBusDepartures=true&FindTrainDepartures=true&HasStepFreeEnabled=false

(bookings will open in 2 weeks time)

Shuttle Bus TT-https://nolancoaches.ie/wp-content/uploads/2023/02/Irish-Ferries-Timetable-V1.pdf

Thanks for the very detailed reply. The Belfast bus station is very close to Hotel Europa, which is the hotel used by the RS tour. That fact, plus the earlier arrival time, make the bus the better choice for us. Also, I was unaware of the IF shuttle bus. I purchased our SailRail tickets, and I've set up a reminder to purchase the Belfast to Dublin bus tickets when that becomes possible.

It will be a long travel day for us, but provided the weather cooperates for the Swift crossing, we shouldn't have too much trouble getting from Belfast to Caernarfon.