The weather in Ireland and Scotland varies depending on the time of year you visit. We would suggest that you pack clothing to layer, a waterproof jacket (there’s a reason our islands are so green!) and a comfortable pair of shoes/sneakers. Apps such as Packr and PackPoint can provide great packing tips based on your destination and the forecasted weather.
Other useful items we suggest you pack include:
Phone charger
Adaptor/converter plug
Medication
Travel iron
Carry/day bag
Reusable water bottle
Travel pillow
Photocopies of your passport, hotel list, travel document and luggage contents for reference