It’s difficult to experience everything Ireland has to offer from the window of a tour bus.

That sort of reasoning is what encourages an American tourist to rent a car and take to the open road. But it’s only when he actually gets into the car and realizes that the steering wheel isn’t where it’s supposed to be that the real action begins. Dodging tractors and barreling over hedgerows — not to mention driving head-on into oncoming traffic — is the kind of spectacle that the people of Ireland would prefer to do without. Which is why, this week, Ashford Castle began offering driving lessons to people who drive on the right — that is to say, wrong — side of the road.

Ashford Castle is a posh resort hotel on Ireland’s scenic west coast, and no driving tour of Ireland is complete without seeing its magnificent 13th-century turrets. But some might say it’s doing its country a service by training Americans in how to drive on the left-hand side.

The peculiar Anglo-Irish penchant for driving the way they do arose, some say, from the fact that it was not how the French drove. Simple enough. Another tale is that in the Middle Ages, a knight on horseback would want to be able to draw his sword and defend himself. Because all English swordsmen were right-handed in those days, riding on the left-hand side of the road was the logical choice.

These days, the French and their Continental cousins are fairly deft at getting into the right-side driver’s seat. Americans are the ones who don’t have a clue on the narrow streets of the Emerald Isle. “Things got so dangerous that Ireland decided not to honor the licenses of Americans who moved here. They have to pass our country’s test to get a license to drive,” a driving instructor at Ashford Castle, David Marsh, said.

“If you’ve never driven on the left-hand side of the road before, you’re going to drift into the right lane when you allow your mind to wander,” he said.

Therein lies the challenge. The Irish countryside in counties Mayo and Galway is filled with ancient ruins, quaint villages, and sweeping seascapes. It’s easy to take your mind off the Irish rules of the road.

Mr. Marsh will remind you that he’s a member of the Royal Society for the Prevention of Accidents — honest to goodness, that’s the name — and that it’s his sworn duty to make certain you continue to concentrate behind the wheel. Daydreaming leads to those precarious lane shifts.

The class, which therefore stresses concentration, takes about two hours. Near the end, if the driver is progressing well, Mr. Marsh throws some sophisticated moves and lessons into the mix.

Géill slí, for example, is Gaelic for “yield.” And the farther away a tourist drives from Dublin, the more likely he is to encounter road signs that aren’t in English.

Mr. Marsh’s favorite lesson is how to navigate the roundabout. There are some priceless movie scenes in which American tourists are unable to break free of these congested traffic circles.

The driving instructor says the trick is to enter in one of two ways. Assuming you approach the roundabout from the 6 o’clock position, bear to the left if your exit is anywhere below 12 o’clock.

If it’s anywhere past 12 o’clock, bear to the right and stay right until you’re one exit away from your own. Be aggressive. Don’t yield to entering cars; you’re the one who has the right of way.

What if you have no idea where your exit is? “It won’t kill you to go ’round one full time,” Mr. Marsh said.

Look over there, kids … Parliament!