In addition of the beautiful Ancient Town Hoi An also offers some diving opportunities. The various sites are all around Cham islands, which are over an hour away from Hoi An in the NAME. In town you can find several dive centres, with ChamIsland Divers and Blue Coral Diving the two main players, and who are foreign owned. Both offer try dives, fun dives for OWD and AOWD and Padi courses. I used Cham Island Divers, but I met someone who did the OWD with Blue Coral Diving, and was very happy with them.
Dive centre: Cham Island Divers
Cham Divers is based in the Ancient Town, inside the Dive Bar. They offer several packages for divers and non divers, including Padi courses, try dives, fun dives, snorkelling – either as a day package or a two day package that include overnight stay on Cham island (sleeping in a tent on the beach). Prices starts from $72
Their boats are spacious, with a large sun deck to relax, space on the ground deck to get some sun protection, and a good platform to get in and out of the water. Water, tea, cakes and bananas were provided free of charge throughout the day. They also had a few books on board to see what fish were spotted during the dive. Very handy for people new to diving. Lunch is not served on board, but on a beach on Cham Island, where the afternoon is spend to relax.