Some important things to remember for your travel and stay at Andaman Islands ~
a) Carry your original ID proof as you need them for most of the ferry rides.
b) Remember to carry your sunscreen lotion (both for face and your body) as the sea water and the sun tans your skin pretty fast.
c) Carry your rain coat and an umbrella if you are going during the rainy season so that you have an uninterrupted vacay.
d) Carry a waterproof cover for your backpack (you will find these on Amazon).
e) Carry Odomos or any other mosquito repellent as you may need them during treks.