I booked a group jungle tour to visit the krabi hot water springs, emerald pool and the tiger cave temple. It is ideal to reach Thailand and book the tours over there as you can negotiate with them and you will get a decent price for all the tours. This tour would actually cost around 700THB. However as I booked it prior from India, I had to shell out extra bucks.
Hot water springs - the best soothing experience. Unfortunately I didn't take a picture of it as I was too busy enjoying the experience.
Emerald pool - enjoy a nice swim after a short hike through the forest decked with crystal clear pools of water all along.
Tiger cave temple - Admire the cliffs, caves and the nature.. 1000+ steps to reach the top. Try if you can!!
Visit the night market in the evening - to buy any souvenirs or just to relish the local delicacies(alongside the one in the pictures, there are lots of non-veg options, the must try pancakes). It's 11km away from Ao Nang, you can either book Grab taxi or go by tuk tuk or your rented vehicle.