Before the 2004 IUCN world congress in Bangkok, I took three days off to go and scubadive in the Andaman Sea. I was based in Khao Lak (one hour North of Phuket) in a nice hotel on the beach which was completely devasted one month later by the tsunami.
For such a short trip, I decided not to take my 40 lbs Ikelite gear but to reuse my good old Nikonos V. Also, the Similan Islands are well known to be a dream place for macro photography, and I had a set of macro rings with frames which make close-up photography really easy. This happend to be a good choice... and a successful last trip for my Nikonos!