Half day trip to Khai Islands. If you do not have much time to go to other islands from Phuket, then definitely recommend Khai Islands – half day trip! Meet up around 9AM and can go back to Phuket island around 1PM. If you join one day trip, return time is around 5PM.
There are 3 Khai Islands and on my trip we visited 2 of big islands and one additional snorkeling near 2nd island. To stay First island(Koh Khai Nai) maybe less than one hour but it is enough to swim and watch colorful fishes. In 3rd island (Koh Khai Nok) we stayed for almost one hour and you can enjoy marine sports not only snorkeling.
Lots of small kids, maybe 2-3 years old, joined this trip so if you travel with small kids, this trip can be enjoyable.
By boat all destination less than 30 mins so if you can get easily sick at boat, I really recommend to this half day trip to Khai Islands.