3 days is not long but enough to discover Hoi An. Here are some Hoi An activities you might consider for your holiday.
Day 1: Take a river boat tour for 2 hours to discover the Coconut village, Kim Bong capentary village, Water life in Hoi An. You will see Hoi An water life, how nature blessed this place with so many breath taking views.
Come back to discover Hoi An ancient town with photo walking tour & Foodie tour. Taking nice photo by professional camera, eating like a locals at many secret hot restaurants, and enjoy your favorite coffee at the cafe shop with the rooftop view of the ancient town.
Go to the beach in the sunset can be unforgetable memories for you.