If you know your dates and can book in advance, then absolutely flying is the way to go; Ryanair fly the route but also Aer Lingus so check them both out (www.aerlingus.com) and see who has the best times & fares.
P&O run a ferry route between Dublin and Liverpool, which would be the closest port to Manchester. The ferry journey is a mind-numbing seven hours, compared to probably 45 minutes flight time... However, there is a fast ferry from Holyhead, a bit further from Manchester but it's about 90 mins sailing, if you really want to get the ferry.
If travelling by ferry, the Holyhead route has most options and is probably the most popular. It can also be less expensive than flying but is obviously more time consuming. Stena Line and Irish Ferries are the two main ferry operators from Holyhead.
Ryanair and Aer Lingus have good deals if you book well enough in advance...Ryanair will sting you for luggage though so just be wary. Flying is the best option if you can manage to book flights at a decent price.
The High Speed Ferry is 120 minutes and doesn't always run, because of weather conditions.
The Ulysses also runs from Holyhead to Dublin and takes 3 hours. Its a lovely ferry and rarely affected by the weather. Most of the time she barely feels like she is moving.
However, I think the plane is the best option. Particularly if you have limited time.
The drive from Manchester to Holyhead takes in wonderful scenery in North Wales but it takes the bones of a day to do the trip - we travel from Manchester to Dublin via Ferry each July and we leave at 9.30am - no later. Stop off for lunch and a quick shop in Llandudno and get the 2.00pm Ferry. We are not on the road until 5.30pm following disembarcation.
we are travelling by car from london back to dublin but stopping in manchester. which is best ferry please? liverpool or holyhead? how long by sea and by road in other words? many thanks
Liverpool is mainly a truckers ferry and takes longer.
This site gives you distance, direction and time of your journey - click on the UK bit http://routes.aaireland.ie/
What we usually do is leave Manchester by 9.30am, latest, then drive to Llandudno. We stop in Asda for school shirts, chocolate and yum yums (don't ask!!) and then take a quick swoop around the town (last trip yielded two pairs of sandals half price and a variety of books...). Then drive to Holyhead and check in an hour beforehand (I know they say you only have to check in 30 minutes beforehand but I like to leave time for problems!!).
I hope this helps.
Holyhead is the best crossing. Liverpool is mainly Freight as said.
Which ferry depends on which crossing best suits. Unlike BeanA who likes the Ulysses I stick where possible to Stena Line and would never consider the IF Swift but it is the fastest way over winter schedule (if its full enough to run,,,sorry if the weather isn't too bad)
The High Speed Ferries are great if the weather is great. If not, then you can have the crossing from hell as we did in July 2009. There were about 10 people on the public areas of (packed) boat who weren't sick. One crew member, a couple of hell's angels and my second daughter myself were in this lucky cohort.
The great thing about cruise ferries (Irish Ferries OR Stena) is that they are far more stable and much larger. We've done the Irish Sea in a F8 and barely noticed it. Similarly we've done the English Channel in some of the P&O older boats (Pride of Canterbury, Burgundy etc) in rough weather and found them comfortable.
Tony - have you taken any of the new ships on the Dover-Calais route? We were lucky enough to take the Spirit of Britain last year and the Spirit of France this year. Absolutely beautiful boats. A destination in themselves.
Last time I crossed to France by sea was Hovercraft!! too easy to fly these days.