The car sits on the left of the lane and the gear lever is by your left hand. Neither of those is the difficulty. Within twenty minutes the lane position stops feeling strange, and in an automatic there is no gear lever to think about at all.

The difficulty is roundabouts, right turns, and the width of the road.

The first 48 hours

Roundabouts run clockwise, and you give way to traffic coming from your right. The failure mode is not confusion on entry — it is the instinct to look left for the gap. Look right. Say it out loud for the first day if that helps.

Right turns are the other one. A left turn keeps you in the near lane and is easy. A right turn crosses oncoming traffic into the far lane, and the mainland instinct finishes it on the right-hand side of the road. It happens most often at quiet junctions with no other traffic to copy — leaving a rural car park, pulling out of a forecourt at seven in the morning.

The classic incident is not on day one, when you are concentrating. It is on day three, when you are tired and you turn out of a driveway onto an empty road.

Two habits that work. Keep the centre line by your right shoulder as a constant check, and let a passenger call “left, left” on every turn out of somewhere for the first two days.

The road is narrower than you are expecting

Ireland’s motorway network is modern, well surfaced and unremarkable to drive.

The regional and local network is a different object. Large stretches are narrower than a single mainland lane, with dry stone wall, earth bank or dense hedge hard against the tarmac and no verge at all. There is nowhere to put a wheel.

Hedgerows grow to head height and are cut back seasonally rather than continuously, so blind bends are genuinely blind. Assume something is coming and drive at a speed that lets you stop inside the distance you can actually see.

On single-track sections the convention is simple and universally observed. Whoever is nearer a passing place stops in it, or reverses back to it, and the other driver comes through slowly. You lift a finger off the wheel to say thanks, which everyone does, and which you will be doing by the second day without noticing.

Reversing fifty metres in an unfamiliar car with walls both sides is normal here. Practise it once, somewhere quiet.

What the road number predicts

The prefix is the best single indicator of what you are about to drive on.

M is motorway. N is national primary or secondary — generally wide, generally fine. R is regional: two lanes in theory, one and a half in practice on the poorer sections, and quality varies enormously along a single route.

L is local. Assume single track with passing places, no markings, grass up the middle and field gates opening straight onto it.

A satnav set to “shortest” will find L roads all day. Set it to fastest and accept the extra kilometres — the N road that looks like a detour is quicker and less tiring.

Journey time is where itineraries break

This is the most common planning error mainland drivers make, and it is arithmetic.

On a French autoroute you plan at 110–120 km/h and you achieve it. In Ireland, off the motorway network, a realistic average is 60–70 km/h, and on rural routes closer to 45–55 once you include tractors, livestock, passing-place negotiations and the fact that you will stop to look at things.

The limits have moved slower, too. Since 7 February 2025 the default on rural local roads in the Republic dropped from 80 km/h to 60 km/h — around 82,000 km of road. National secondary roads are due to fall from 100 to 80 km/h during 2026, so read the signs rather than your memory of a previous trip.

The working rule: take whatever your mapping app predicts for a non-motorway Irish route and add a third. Then plan three hours of driving in a day, not six. The Ring of Kerry is about 179 km and it is a full day, not a morning.

Two sets of speed units on one island

The Republic posts limits in kilometres per hour. Northern Ireland posts them in miles per hour. The road does not change; the sign does, at a border with no marking.

As of mid-2026 the Republic’s defaults are 120 km/h on motorways, 100 on national roads, 80 on regional roads, 60 on rural local roads and 50 in built-up areas. Northern Ireland uses the UK nationals: 70 mph on motorways and dual carriageways, 60 mph on other single carriageways, 30 mph in built-up areas.

So a sign reading 60 means 60 km/h on one side of an invisible line and 96 km/h on the other. Irish hire cars show km/h as the primary speedometer scale with mph in small figures inside it — check which ring you are reading.

Automatics are scarce, and dearer

The Irish fleet is overwhelmingly manual. Automatics cluster in the larger, more expensive categories, and demand outstrips supply from May to September.

If you want one, book months out and treat “or similar” in the confirmation as a real risk — confirm the transmission specifically, in writing. A walk-up automatic in Dublin in July is either unavailable or priced as a luxury category.

Given the roads above, an automatic is worth more here than at home. Changing gear with your left hand while judging a hedge-lined bend is a lot of simultaneous novelty.

Fuel, and the pump colour trap

Petrol is called petrol, not essence or benzin. Diesel is diesel. That part is easy.

The colours are not. In Ireland the unleaded petrol nozzle is green and the diesel nozzle is black. Several mainland conventions run the other way, with black or grey for petrol and green marketed as the clean diesel. Reaching for the familiar colour is exactly how misfuelling happens.

Read the word on the nozzle, not the colour. Then check the sticker inside the fuel flap, and the fuel type printed on the rental agreement beside the registration.

Misfuelling a hire car is a four-figure event and the desk waiver usually excludes it. Rural forecourts sometimes sell agricultural diesel from a separate pump; if the only green-nozzled pump appears to be diesel, go in and ask.

The M50 has no barrier

Dublin’s orbital motorway is tolled electronically between junctions 6 and 7. No booth, no barrier, nowhere to stop and pay. A camera reads your plate at motorway speed and you notice nothing at all.

You then have to pay it yourself, online or by phone, by 8pm on the day after the journey — cross at 23:00 on Saturday and you have until 20:00 on Sunday. Miss it and the charge escalates in fixed steps: a small late fee, a substantially larger penalty after a fortnight, a larger one again, then enforcement.

Passenger car rates from 1 January 2026 are €2.60 with a tag, €3.20 on a registered video account and €3.80 unregistered. The toll itself is trivial. The escalation is not, and the hire company will add its own administration fee to whatever reaches it.

Ask at pickup whether the car carries a toll tag and how tolls are billed, because many Irish fleets are enrolled and paying online as well means paying twice. If it is not enrolled, note the date of every M50 crossing and clear each one that evening.

Ireland’s other tolls are conventional barriers where you stop and pay. Only the M50 works this way.

Parking discs

Larger towns run pay-and-display machines and, increasingly, app payment. Smaller towns still use paper parking discs, sold in newsagents in books of ten: scratch off the date and time and put it in the windscreen. If a town centre has no machines but every parked car has a small paper square on the dashboard, that is a disc town.

Sheep

They are on the road, they are the colour of wet tarmac, and they do not move for a horn.

Sheep, cattle being walked between fields and unlit farm traffic are ordinary hazards on R and L roads, particularly in Kerry, Connemara, Donegal and the Wicklow uplands. Hitting livestock means finding the owner and making a Garda report — a day gone.

Northern Ireland is the exception

Everything above assumes the Republic. The North differs in ways that catch people mid-trip.

The currency is sterling. Limits are in mph. Fuel is sold in litres on both sides but priced in different currencies, so a cross-border pump comparison means nothing until you convert it.

Breakdown cover is frequently written per jurisdiction, and your hire agreement may or may not extend across the border at all. That is arranged at booking, not afterwards, and one-way drop-offs across it are often refused outright.

The genuinely simple part: there is no immigration control between the two, and Irish citizens need no UK Electronic Travel Authorisation.

Before you book: the deposit

Irish hire deposits and excesses behave differently from the mainland norm, widely enough to change which card you bring — compare Irish hire quotes with the deposit hold shown before you commit, and read the excess guide first.

How we make money on this

Half the advice here is about refusing the counter products that pay best — we’d publish it either way.