Driving on the left: If you have spent your life driving on the right, this can take getting used to. I strongly suggest that you do not drive tired and be very careful for the first few days.
Roundabouts: Not usual in the USA but everywhere in Ireland. Give way to traffic on your right before entering the roundabout.
Gas in liters: This is strange when you are used to gallons. There's just under 4 liters to a gallon so multiply the liter cost by four to get the price you are paying for a gallon. Prepare for sticker shock!
Service Charge: Many restaurants, especially tourist places, add a service charge automatically to the bill. This is usually between 12 to 15 percent, so be careful you don’t tip twice as it happens quite a lot.
Distances in kilometers: This can also be quite confusing when you're used to miles. One mile is 1.6 kilometers. When you're trying to judge distance, five miles is 8 kilometers, 100 miles is 160 kilometers etc.
European plugs: Your two-pronged US plug won’t work without a three-pronged Irish adapter. Many hotels supply one but don’t bet on it. Make sure to buy a European adapter before going or pick some up at the airport.
Pack a set of warm clothes: Make sure you include rain gear, even in summer. To wrongly paraphrase Mark Twain, the coldest winter’s day can be a summer’s day in Ireland. The weather is very changeable at times so be prepared!
No coffee refill: You will wait in vain for that diner or coffee shop for the waitress to refill your cup. Tea drinking is much more popular in Ireland and the extra coffee refill is unknown.
Baseball? What’s that? If you're hoping to keep up with baseball scores and your favorite team, the Irish papers and sports channels, which are utterly dominated by soccer and Gaelic sports, will have none of it. This isn't quite as big a problem since the dawn of the internet and instant game updates. (As long as you have WiFi.)
When the Irish made time! Don’t expect friends, cousins, and relatives to be on time if you have arranged a meeting. Letting things slip 15 minutes or so is a way of life you will find yourself relaxing into pretty quick!
* Originally published in May 2015.