Pack any prescription medications you require, along with basic over-the-counter drugs like pain relievers, antihistamines, and medications for upset stomachs. Since many islands are only accessible by seaplane, it may be difficult to find chronic medication or anything prescription-based. Also, include any personal hygiene products you typically use, as some toiletries might be limited or expensive on the islands.
Bonus Tip: Pack a reusable water bottle to stay hydrated throughout your trip. Most resorts offer filtered water, so you can refill your bottle and avoid single-use plastic.