Hello everyone ! 
I currently have a Visa ED for 90 days but i stay in Thailand for an internship in Ko Samui, wich is during 6 months. I saw that it can be renewed for one year, but I’m wondering how does it works and wich papers i need to give ?
TLDR : Answer Summary
The user currently holds a Visa ED valid for 90 days and is seeking to extend it for their 6-month internship in Koh Samui. They inquire about the renewal process and required documentation. A response suggests that it might be challenging to obtain the necessary documents for the extension from the company they're interning with. It is recommended to visit the Koh Samui immigration office for further assistance, with a note that previously, interns would often obtain a Non-ED visa for an additional 90 days from a Thai consulate overseas.
90 DAY REPORTING RESOURCES / SERVICES
- Use the trusted Thailand 90 Day Reporting Service to get your in-person report done and mailed to you for as low as 375 THB (even if the online system doesn't work for you).
 - For immediate assistance, contact Thai Visa Centre directly via LINE at @ThaiVisaCentre or Email them.
 - Join the Thai Visa Advice Facebook Group to ask your questions, and get advice from others.