Sawasdee Krub.
As a general rule, I always ask the locals if its ok to fly the drone in "their area" + offer to send them a couple of pics of their place/house by email or Line.
You will need to seek permission to fly the drone inside or near Sattahip Naval base and Nang Ram beach is a tad too close to the Naval base I think, so I suggest you start by asking the locals on the beach and if you start flying, then dont fly too high. There are the occasional helicopters flying in/out very low + Utapao Airport is app. 15km from the Nang Ram beach. As always fly with caution and dont fly higher than what you really need!
I had to seek permission in regards of a project we handled via Sattahip Commercial Port and it took a couple of days, but was easy to get since our company was client to Sattahip Port. When we asked the Navy they joked and told us "no drones" only helicopters - and I was seriously hoping for an invitation to go on a bigger bird, but then sadly got permission to fly the drone
@ Filaofsoul Sattahip is indeed a very nice place. Give me a text if you ever plan to come back to TH and Sattahip, I would be happy to show you around on the naval base and it would be very interesting to hear about all the changes that has happened since your active days at Kilo 1. Do you have any pictures from that time? I would love to see some of them, if you dont mind to share?
BR
Thomas