10 great ferry routes: From Santander to Stornoway, ships to take you the extra nautical mile

Ireland's sunshine coast, a great day out on the Isle of Man, and no frills Portsmouth-Santander

Poole-Channel Islands: high life on the high seas

Starting next month, Condor Ferries (condorferries.com) will be operating a new fast ferry between the Dorset port and Guernsey/Jersey. The £50m Condor Liberation will cruise at 45mph. For bookings made during National Ferry Fortnight (2-15 March), the line is offering a free upgrade to Ocean Traveller Plus – allowing access to a premium lounge providing excellent views – if you book online and use the code NFFUPGRADE.

Dover-Dunkirk: maritime connection

France's northernmost city has a fine harbour and a fascinating maritime museum, the Musée Portuaire, which documents Dunkirk's place in both war and peace time. The port also has some of France's best seafood restaurants and miles of sandy beach. DFDS (dfds.co.uk) serves the city – docking some miles west – from Dover. Between now and the end of June, a five-day return for a vehicle and up to nine passengers is £59.

Isle of Man: great day out

Despite its quaint name, the Isle of Man Steam Packet Company (steam-packet.com) has a fleet of modern ferries sailing from Heysham to the island. The "Footloose" day return starts at £29. If you don't mind an early start, it allows up to 14 hours on the island.

Aberdeen-Northern Isles: deep savings

Northlink (northlinkferries.co.uk) sails between mainland Scotland, Orkney and Shetland. The value of its National Ferry Fortnight deal is shown by the rule that it applies to new bookings only. Call 0845 6000 449 and quote D15DF3/NFF by 15 March for a 30 per cent discount on standard passenger and vehicle fares. The offer does not apply for sailings in late June, July and August. Happily, the far north of Britain can still be at its shimmering best in early June and September.

Portsmouth-Santander: no frills

A month from today, Brittany Ferries (brittanyferries.com) starts a low-cost service from Hampshire to northern Spain, sailing Saturday mornings at 8.15am and arriving 26 hours later. Don't expect the "cruise ferry" experience normally associated with Brittany Ferries, but do expect low fares: from £244 for a car plus two passengers.

Hull-Rotterdam: two for one

P&O Ferries' (poferries.com) overnight sailing from Humberside to the Dutch facility, Europoort, provides up to eight hours in the Netherlands' leading architectural hub. Rotterdam has been spectacularly rebuilt since the destruction of the Second World War, and is comfortably accessible on a two-for-one special deal in Spring – as low as £79 return, including a cabin and the bus connection from the port to the city.

Dover-Calais: car carnet

Commit to booking at least three return crossings on MyFerryLink (myferrylink.com) and you pay a maximum of £80 for each round-trip outside the school summer holidays. You can travel on peak sailings by paying a modest supplement. Book on 0844 2482 100.

Penzance-Isles of Scilly: children go free

Fares on the Scillonian III (islesofscilly-travel.co.uk) between Cornwall and the Scillies' main port, St Mary's, are among the highest per-mile in Europe –£43 one-way for a foot passenger on the three-hour sailing. So if you plan an Easter family escape, then call 01736 334220 quoting NFF15: when two adults travel together, two children go free. It applies only in March and April, and not on Mondays or Fridays.

Pembroke-Rosslare: Ireland's sunshine coast

Don't expect Costa del Sol temperatures on the coast of Counties Wicklow and Wexford, but the area around the south-eastern port of Rosslare has remarkably low rainfall in May and June – significantly less than Ireland's west coast. For National Ferry Fortnight, Irish Ferries (irishferries.com) is promising one passenger travels free to and from Ireland on car bookings made from today until St Patrick's Day, 17 March, for travel throughout 2015.

Western Isles: wild rover

Caledonian MacBrayne (calmac.co.uk), winner of the UK ferry operator of the year title at the National Transport Awards, has a remarkable "Rover" ticket that allows unlimited travel through its entire network. An eight-day ticket for a car plus two people costs £380. You can sail on any crossing you wish, but advance booking may be necessary for some busier sailings. Book on 0800 066 5000.

For more information, see bit.ly/FerryFortnight15