( Find up to date information in the Koh Kood guide. )
A couple of weeks ago some guests arrived at our guesthouse from Koh Kood. They were about half an hour late. I asked them what happened as the weather was good and they didnt seem at all bothered by the delay. Turned out that they had seen a pod of around 50 dolphins on the way from Koh Kood to Koh Mak and the speedboat stopped so everyone could watch them.
This video was taken in the same area at about the same time. ( Ignore the title of the video, the island you can see isnt Koh Chang it is Koh Kood.) If you like this there are several additional parts of the video posted on Youtube.