In Ireland, it's not unusual to experience all four seasons in one day. So no matter the season, you need a warm sweater or fleece jacket, a waterproof jacket and good walking shoes/boots for all sorts of terrain. An umbrella is always handy, and bird watchers may wish to bring binoculars.

The golden rule for packing for Ireland is to dress in layers, as the weather is famous for changing "four times in one day." Even in summer, temperatures rarely exceed 20°C (68°F), so you should always have a high-quality waterproof rain jacket with a hood; umbrellas are often useless against the strong Atlantic winds. Your base layer should include breathable T-shirts, followed by a middle layer like a fleece or wool sweater, which is easy to remove if the sun comes out. For footwear, waterproof walking shoes or boots are essential, especially if you plan to visit rural areas like the Cliffs of Moher or the Ring of Kerry where paths can be muddy. Don't forget a Type G (three-pin) power adapter and a portable power bank, as you'll likely use your phone's GPS frequently for navigation. Lastly, leave room in your suitcase; Ireland has excellent shopping, and you may find yourself wanting to bring home a heavy Aran wool sweater or a locally made tweed cap.