On Cham Island you will not find too many accommodations. I passed a nice looking homestay on the main road along the beach in the village of Bai Lang, though I don’t know what the rooms are like. There are one or two further places to stay north of the village – just take the road up the hill from the pier and passing the football pitch.
In the other village, Bai Huong, there are apparently some homestays, but I cannot advise where.
One popular option at the island is staying on Bai Chong beach – in a tent. It is part of some trips organised by the dive outfits in Hoi An. Here is my review of my stay there.
If you want to stay in a tent away from the beach the Ecological garden Hill is a place to consider. It is located above Bai Chong beach. Just take the steps up from the beach to the road and turn left and head up the stairs you pass a minute later. The owner of this place is very friendly and shows you happily around the area that icnludes planations, well, gardens – and a little area for beaches. It is very basic here, but it looked nice. And the view from there is to die for.
Overall I would aim to stay at one of the homestays in Bai Lang as it is a nice chance to experience the rural life here. If you are doing a 2 day dive trip with an overnight stay, check if they can arrange a room at a homestay as well.