Thai Regions

Northern - Chiang Rai & Chiang Mai
Also episodes 2-3 & 4 of the mini series included in the Our Skyy 2 anthology (Story 8 & 9) - Chiang Rai

Northern

Northern - Chiang Rai. This one focuses on the boys, coach, families and other locals more than foreign rescue workers.

Northern - Chiang Rai. Focus on boys, Thai people and region. 

Northern - Chiang Rai. Focus on rescue, but also shows Thai region.
(Foreigners to the rescue. If you want to learn more about the land and people, The Trapped 13 is far better - Eli)

Elisheva: "Northern, from MDL comments haven't seen to confirm yet"

Northeast - Phon Phisai district, Nong Khai province, across Mekhong from Vientiane. It's about the fireballs. VERY local, strong sense of place.

Northeastern - Isaan

Northeastern - Isaan

Northeastern - Isaan

Elisheva: "I'm pretty sure this is Isaan from the landscape and mor lam soundtrack"

Elisheva: "Northeastern I think, haven't seen yet. MDL page says Central but Chaiyaphum Provice is just over the Northeastern border on both the four- and six-region systems. I'm not an expert though, just a geek."

Northeastern - Dan Sai district, Loei Province, Isan - Thai PBS

Village on the Cambodian border, and that matters in the story. That could be either Eastern (6)/Central (4) or the bottom of the Northeastern region. Maybe someone else will know.

Central/Eastern - Rayong Province (Raw easy to find but I haven't been able to track down Engslish subtitles. If you find some, give me a shout na- Eli)

Central (4)/Eastern (6) - Pattaya City, Chonburi
Very strong sense of place, although the Chinatown and diner location used for filming weren't in Pattaya City. I'll have to figure out where I read that, but I think it's still Eastern/Central Thailand - Eli

Based on a floating school in Li District, Lamphun province (Northern) but filmed at Kang Ka Jan Natural Park, Phetchaburi Province (Western, on the border with Myanmar). Chiang Mai is mentioned and the distance probably makes more sense plot-wise for an intended Northern location than Phetchaburi, but it's not made explicit in the film. - Eli

Western (6)/Central (4) - Klity, Kanchanaburi. Very strong sense of place, beautifully filmed, quietly powerful. DM me if you need help finding this. - Eli

Elisheva: "Central (4)/Western (6) (I'm reasonably confident this is partially set in Erawan National Park waterfalls, Kanchanaburi Province 120 km west of Bangkok, with its 7 levels of waterfalls and connection with elephants)"

West/Central - Dan Makham Tia district, southern Kanchanaburi Province. Folk horror with a strong sense of place.

Bangkok

Set in a Muslim district on the edge of Bangkok and in the South-East (Bala forest in Waeng and Sukhirin districts in Narathiwat province)

Southern, Thai PBS

Southern (Krabi) "ethnofiction" not big on context, where it's often unclear what's real and what's fiction but Krabi is very integral to the movie.

South - Surin Islands in the Andaman Sea (below Burma), Phang-Nga province, Moken people.

South - Betong, Yala Province (the southern-most tip of the southern-most province)
It's only set there for a few early episodes but it is a rare chance to see this part of Thailand. The rest takes place in a hospital in Bangkok but doesn't show anything of the city. Those episodes could be anywhere so I wouldn't count this as two regions.

Chiang Mai, Saraburi, Kanchanaburi, Pak Chong & Khao Yai

Northeastern - Isaan

Northern - Chiang Mai

Northern

Northern - Chiang Mai

Northern - Chiang Mai

Northern - Chiang Mai

Northern

Northern - Chiang Mai

Northern - Chiang Mai

Northern - Chiang Rai

Center - Ayutthaya