The weather on the islands can be very different to that on the mainland. So do be prepared. Here’s some essential kit to take:
Map, compass, GPS and phone – many of the routes will require good navigational skills in the absence of an official coastal route. The same rules apply if you were walking in the mountains. Visibility can disappear quickly and some routes are harder to find.
Water – make sure you have enough or check that you can replenish your stores on the island
Food – take enough with you for your visit plus a bit extra if there are no facilities. Islandeering is a hungry business!
Waterproof/windproof shell – I can’t think of many islands that haven’t been at least a bit windy. Waterproofs and Scotland? Say no more.
Warm layers – including hats and gloves if necessary. You’ll be spending most of the day out at sea where it is generally cooler. You might also need an extra layer for the ferry trips which can be quite breezy too.
Appropriate footwear – this could be walking boots or beach shoes for mud and water crossings.
Sunscreen – it’s easy to get burnt when the wind is blowing. You know it makes sense.
Tide timetables & ferry timetables – don’t rely on being able to find this information out on the island or getting a good enough signal to google it. Be safe. Take the timings with you just in case.