I found several places selling open water wetsuits in Hua Hin:
* Hua Hin Divers is 6.5 km away. It has a 4.4 star rating on Google Maps.
* Duotone Kiteboarding Club - Kiteschool Thailand is 7.7 km away. It has a 4.9 star rating on Google Maps. It is open from Monday to Sunday from 9:00 AM to 6:00 PM.
* Efoil Thailand - Hua Hin is 7.9 km away. It has a 4.7 star rating on Google Maps. It is open from Monday to Sunday from 9:00 AM to 6:00 PM.
* Surfspot Huahin is 8.1 km away. It has a 4.4 star rating on Google Maps. It is open from Monday, Tuesday, Thursday, Friday, Saturday, and Sunday from 10:00 AM to 5:00 PM.
* KBA Kiteboarding Asia HuaHin
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- Kitesurf, Wingfoil and Efoil Center is 8.2 km away. It has a 4.7 star rating on Google Maps. It is open from Monday to Sunday from 9:00 AM to 6:00 PM.
I hope this helps!