A quiet but beautiful place, ideal place for relaxation. Find a beautiful boutique resort and stay there for a night or two, you won't regret it.
You will leave Satun a contented person, without worries (but I a not sure how long this feeling will last once you return to the "urban jungle"!)
Sayun is a great place for a short stay if you are on your way to Langkawi by ferry, or the other way, to HatYai for shopping or further travel.
In itself, the city does not have a lot to offer a tourist, so 1 or 2 days is enough. Try to time it for the Saturday NIght markets which are a great place to sample foods and buy clothing.
We drove to Satun from Bangkok, the roads in the province are in good condition and the tourist sites are well signposted.
You can go to Malaysia by road, or by the ferry from Tammalang Pier (about 8Km south of the city) to Langkawi. Pak Bara Pier, some distance to the west, is where you go to get to Tarutao and the other islands in that National Park. There are varoius other national Parks. Phu Pha Phet cave - currently the 4th largest in the world has walkways and low lighting which allow you to visit huge chambers on two levels. Jet Kod cave nearby can be visited by canoe but only (I think) on a tour. There are various other caves and a number of waterfalls in the provonce. Satun itself is slowly developing and has acquired Big C, Tesco and Makro on the outskirts. The centre has some delightful areas and the museum - called Kuden Castle (or mansion) is first rate with modern technology for the displays and everything in both Thai and English. Public transport exists but this ,naturally, is designed for the locals. However one can rent various forms of road transport or a long tail boat to visit the mangrove swamps and Tham Lot Phu Yu (a cave through a cliff) + another cave nearby if you use what is is termed a canoe. Takes about two hours.
close to basic life, not really for tourism but if you want to understand Thai live at it's simplest